When the game starts, we are greeted by the main menu. It looks like this:

The "Single Game" tab is responsible for single and local play with friends. There you can see a list of your cards and configure the upcoming game on the selected map.

• Max ammo - The maximum amount of ammunition you can carry with you;
  
• Give weapons on spawn - When you respawn you will receive the HL2 arsenal;
  
• Players have god mode - God mode for all, you cant die;
  
• Enable HEV Suit - Enable HEV suit function;
  
• Enable realistic fall damage - Realistic fall damage.

• Local Server - Your computer creates a local server;
  
• Peer-to-Peer - Your computer creates a public server;
  
• Peer-to-Peer: Friends Only - Your computer creates a server for only friends.

In the "Find multiplayer game" tab, you can find online servers for different Gmod modes. There are also settings in order to filter the servers, and see only those that may be interesting.

• Internet - Online servers that are publicly available;
  
• Favorites - Servers added to favorites;
  
• History - List of servers you played on;
  
• Local Network - Servers on the local network;
  
• Refresh Listings - Update server lists;
  
• Legacy Browser - A classic list of servers for games running on the Source engine opens.

Sort by:

• Player count - The more people, the higher the mode in the list;
  
• Server count - The more servers, the higher the mode in the list;
  
• Gamemode name - The modes are set alphabetically.

Filter by:

• Roleplay - Modes and servers on the theme of role-playing games (DarkRP, Star Wars RP, MilitaryRP);
  
• PVP - Game modes based on the confrontation of players (Zombie, TTT);
  
• PVE - Modes where players fight with NPCs (Horde, Half Life COOP);
  
• Other - Other modes;
  
• Uncategorized - Everything else (Melon bomber, Bunny Hop).

The "Addons" tab is a list of downloaded addons from the workshop:

• Subscriptions - Installed addons;
  
• Trending - The most rated addons for the week;
  
• Top Rater - Most rated addons of all time;
  
• Latest Uplouads - Recently uploaded addons:

• Followed - By subscribing to a person in the incentive, you will be able to see new addons from this person;
  
• Favorites - List of favorite addons;
  
• Friends Uploads - Addons that your friends have created;
  
• My Uploads - Addons created by you;
  
• Open Workshop - Opening a Steam workshop.

▼▼Addons Filters▼▼

• Gamemodes - Addons, which are game modes that completely change the gameplay;
  
• Maps - Addons related to maps;
  
• Weapons - Addons related to weapons;
  
• Tools - Addons related to tools;
  
• NPC - Addons related to NPC;
  
• Entity - Addons related to the entity;
  
• Effects - Addons related to effects;
  
• Transport - Addons related to transport;
  
• Models - Addons related to models.

Filter by:

• Enabled only - Shows downloaded enabled addons;
  
• Disabled only - Shows downloaded disabled addons:

Sort by:

• Name - Sorts all addons by the first letter in the name of the addon;
  
• Size - Sorts all addons by size (the largest addon at the very beginning, the smallest at the end);
  
• Update date - Sorts all addons by the latest updates;
  
• Subscription Date - Sorts all addons by subscription date (new addons on the first pages, old ones on the last).

Interaction with addons:
Select all - Selects all addon in subscriptions;
Select Page - Selects the addons page in subscriptions;
Enable All - Turns on all addons in subscriptions;
Turn off Everything - Turns off all addons in subscriptions;
Delete All - Delete all addons in subscriptions.
Create a preset - Create an addon assembly;
Download the preset - Download the addon assembly.

Duplicates are the same as addons, but made with the help of in-game tools and things (buildings, mechanisms, transport, and other):

• Posing - Duplicates related to mobile models;
  
• Scenes - Duplicates related to immobile models and objects;
  
• Machines - Duplicates related to mechanisms;
  
• Transport - Duplicates related to transport;
  
• Buildings - Duplicates associated with buildings;
  
• Other - All other duplicates.

Saves are a thing that allows you to save your current buildings all over the map. You can also playing on other people's saves and see what people have built there.

• Posing - Saves related to mobile models;
  
• Scenes - Saves related to immobile objects and models;
  
• Machines - Saves related to mechanisms;
  
• Transport - Saves related to transport;
  
• Buildings - Saves related to buildings;
  
• Other - All other saves.
  
  
  ▼▼Demos▼▼
  Demos - these are your and other people's videos:
  
  
  ▼▼Settings▼▼
  The settings represent the general settings of the game, graphics, keyboard and mouse, sound, and so on.
  

• Weapons and NPCs will not be added with this content, ONLY props and models (sometimes there are NPCs);
  
• Without CS:Source content, you can forget about playing on most maps and servers, but we'll figure it out anyway, but a little later;
  
• You can include only those games that are in this list:

Short video guide:
https://youtu.be/gO8qUfp7y-U

Link to CSS Content: http://mp.ru.net/cloud/css.zip

Let's start with the fact that you must have the game on your account, and end with the fact that it must be downloaded from you. From the whole list, Left 4 Dead 2 is right for me right now, so I'll choose it.

To turn on the content, I select the "Games" button in the main menu, which is located in the lower right corner and click the check mark on the L4D2 icon.

We pinch Q and lower our gaze to the lowest icon with the inscription "Games", click on + and see a new tab, where we also click on + and see all the added content.

Spawnlist is a list of created content in the form of: props, models, mods (content), games on the Source engine.

Weapons are a list of available arsenal to use (+mods).

The Entity tab contains consumables from games (mods) and all sorts of tools for influencing the world (cubes for influencing the skybox of the world).

The NPC tab contains basic NPCs from HL2 (+mods). Also, if you have downloaded episodes of Half Life 2, then you will see NPCs from these games.

The transport tab contains the basic transport from HL2 (+mods). Also, if you have downloaded episodes of Half Life 2, then you will see the transport from the episodes.

The "Post-processing" tab contains filters for the screen screen.

A separate guide on this topic:
https://steamoss.com/sharedfiles/filedetails/?id=2969259718


Objects will move freely around their axis like a car wheeel
https://youtu.be/R7WoiTAoAt8

It works like welding, but leaves the objects with their separate physics

Very elastic rope version,fits well for catapult
https://youtu.be/VaOSpQYaNMI

It works like welding, but has rope and movements when the button is pressed
https://youtu.be/nwZzKXCtcnE

When using the numpad, the effect of compression and decompression works
https://youtu.be/16639vfZniY

A rope that moves freely between two given points and that can only move between them

An ordinary rope that drags a prop like a leash with a dog

It works on one axis, opens and closes like a mobile door,works from your direction to physics gun in the side
https://youtu.be/Rwwuge-quDg

Attaches objects to each other

A rope whose length can be adjusted in real time


Flying ballons,they can lift an object into the air

It works very simply, we put a button, we put another object from this list, everything works
https://youtu.be/pNMDPqjpeWk

With the help of a duplicator, you can copy and save any buildings

Explodes and kills

Effects

A very useful and interesting thing that makes objects fly conveniently
https://youtu.be/2jkNRCP950w



Turns off the collision

Prop dancind (:3
https://youtu.be/EWxToirUVEQ

Deletes the item you've been homing in on
https://youtu.be/w1bkxWse6xw

Objects can fly thanks to a jet engine
https://youtu.be/vDIT7kv7gAM

Moving wheels to create a car
https://youtu.be/pGAVRZpIqXE


A convenient way to make the NPC look at one point
https://youtu.be/h3Q96hvr0RA

It's fun, but it's perfect for creativity
https://youtu.be/n1eLkAYFupc

You can move your fingers (who would have thought)
https://youtu.be/n4cX8vAJ_ZU

OKAY THIS IS JUST REALLY FUNNY
https://youtu.be/p_C4TFNGi98


A useful thing that helps to look from the camera's face


It's like color, but texture

extures of what can be on walls, ceilings and props

A separate guide on this topic:
https://steamoss.com/sharedfiles/filedetails/?id=2962459998

Let's start with the simplest
To turn on Menu, we need to hold down the C key, and visit any Subject.
It doesn't matter what it will be, even if the NPC is even transport, there is no difference, in my case it is propaganda.
After we hover the cursor over the object we need, we Right-click on it
It will look like in the picture below


This function does not allow the object to roll over on its side.

Sets fire to the object. Can break the destructible object. The fire does not pass from object to object, only what you have chosen will burn.
Deals damage if you touch it and continues to burn in the water.

A function that deletes the object you selected.

Using the "Manage" function, you will be able to control any object from a third person. It is possible to fly through any obstacles (including through the map).
While your camera is flying, your character will stand in the "Telekinesis" pose, putting one hand to his head, and the other will point at the object he controls.
To exit the control, you need to either delete the object using "Z" or press the English key "E".

Thanks to this function, you can walk through objects and all other objects will pass through them (exc. map).

When using the function, gravity will not work on the object. It starts to fly smoothly, but in order for him to start doing it, he needs to be pushed.

Body groups are something that can mostly be found in mods. Thanks to this function, you can change certain parts on the NPC, models or item.

Skin as a body group, only replaces the entire appearance of the object at once.

To begin with, this function can only be used on "Edible balls" and "Cubes changing the background" (I haven't found it anywhere else)
Thanks to this function, you can change the color of the ball or its size, and on the lips you can change the range of clouds, sun and other things


The function for changing the bones of the NPCs can be called one of the most fun, because thanks to it you will be able to stretch the limbs of the NPCs in different directions.

Thanks to these functions, you can both increase and decrease the NPC, and its hitbox can also change along with the NPC itself.

The static function can make a mobile statue out of a model, which can be moved with the help of a physical gun.

A separate guide on this topic:
https://steamoss.com/sharedfiles/filedetails/?id=2981737066

The Utilities button can be found by holding down the Q key and looking to the right side of the floated panel

It is worth saying that the user settings are responsible only for the settings in relation to you. This will not affect the game of other players in any way.
In fact, these are interface settings. Whatever you choose here will just show or not show a certain effect.

It is mainly needed to clear the entire map, but you can also clear many other objects separately

• The display of the glow - when lifting the physical affect the contour of the prop, highlighting it
  
• The display of the rays of the physical cannon - speaks for itself, turning it off you will not see the beam
  
• Display of freezing effects - affect the effect when pressing the PCM while holding the prop
  
• Displaying the effects of defrosting, the same as freezing, only vice versa

• The interface is HP cartridges - changing the object in the hands of the mouse wheel.
  
• Information about the tools - these are tooltips when you select a function to use.
  
• Instrument effects - this is a pancake that appears when you press the left mouse button with a toolgun
  
• Tooltips of the world - these are the hints that pop up when using the tool
  
• The creation effect - is the dry creation of an object immediately,without animation, as if it appears over time only very quickly
  
• Rings of effects - affect the same pancakes when spawning items
  
• The display of cameras - affect the visibility of cameras
  
• Displaying pushers - affect pushers

A function that allows you to delete everything that you have set, with one click of the LMB on the line you need, from priests to tools


Everything is the same, just cleaning everything, not just your props

• Maximum beam range - beam length adjustment
  
• The maximum speed of the object - the lower the more difficult it is to raise the throughput
  
• The maximum turning speed - the lower the harder it is to turn.

• Giving weapons when reborn - gives us most of the arsenal from HL2
  
• Invulnerability - speaks for itself
  
• Damage between players - is like invulnerability only you can still take damage from other things
  
• Allow flight mode - enables noclip
  
• Changing NPC bones - allows you to change NPC bones
  
• Changing the players bonus - allows you to change the players' bones
  
• Changing the bones of everything - allows you to change the bones of everything
  
• The sliders are no longer so important - since these are the settings that are available before you start the game
  
  
• Sliders
  
• Gravity - affects the jump
  
• Ground friction - works like ice
  
• The speed of physics - changes the speed of physics
  
• Flight speed - changes the flight speed
  
• Maximum Ammo - setting your maximum ammo for all your weapons

• kick for clientside errors - is useless to expel for clinical errors
  
• Allow client scripts - apparently creating sites in gmod...?
  
• Stick to the ground - without it you can slide down slopes and jump like in hl2 speedrun
  
• Lifting items - is the basic function of the game
  
• Realistic fall damage - deals you more height damage when falling.
  
• Enable the functionality of the HEV suit - when activated, you get an additional suit interface

A separate guide on this topic:
https://steamoss.com/sharedfiles/filedetails/?id=2971158847

Hold down Q, open the NPC tab and click on the square


The section with "Animals" contains only 4 NPCs.
3 of them are just birds that include crows, pigeons and seagulls.
But what is Father Gregory doing there? Everything is even too simple as you might think at first glance, this is a simple mistake or a joke from Garry.

This is a section with hostile soldiers and their equipment from HL2 or just Combines.
It represents little of interest, because all this has already been perfectly shown in HL2.
But, these NPCs, together with the NPCs from Humans + Resistance, have one isolation that we will move on to a little later.

This is a section consisting of key and partner NPCs from HL2, they can join the player's squad and fight with the NPCs from the Combine tab, they also have some feature that we will move on to again later.

"Nexbot" is a section containing a Test NPC, most likely it was made to test the animation of these same NPCs. Also, if you download a mod that says "Nexbot", then it will appear in this tab.

This tab contains Zombies, antlions and similar monsters from Zen, except Vortigonts.

And so, to control the NPC, we need to hold down Q, then select the "NPC" tab and then its settings will be available to you.

is a feature that allows you to literally stop time for NPCs

NPCs live their own lives, but they don't care about you

By enabling this feature, all the NPCs you killed become Ragdolls and you can now play with them.

If you have this function enabled, then NPCs will follow you as in HL2, and a window with the number of these NPCs will appear in the lower right corner.

Thanks to this feature, you can issue any weapon to the NPCs.


what this botton do..?

The name speaks for itself, using this function, the Toolgun will immediately be held in your hands, using it you will spawn the NPC you need

A separate guide on this topic:
https://steamoss.com/sharedfiles/filedetails/?id=2911272652

Play singleplayer at least once.

Play multiplayer at least once.
It's enough to join to a friend's server without addons

Play a gamemode that isn't sandbox.
This achievement is obtainable only in multiplayer. In the server list DarkRP, TTT and Jailbreak servers are most popular. To get an achievement, you can connect to such server without installing junk server data (character models, addons, etc.). To connect to the server faster and avoid downloading junk files, go to Settings → Network mode → Download maps only. This setting is required, otherwise you'll not be able to appear on the map and you'll not get the achievement.

Experience 500 Lua programming errors.
In fact, you don't have to waste time looking for a broken addon with a bunch of errors. Just enter this into the console and wait a few seconds:

After you got the achievement, restart the game.

Play 20 different maps.
You need to be on the map for at least 10 seconds for the map to count. This achievement is easy to get if you have installed one of the old Valve games on the Source engine (Half-Life 2, Portal, Counter-Strike: Source, Team Fortress 2). If you don't have these games, you can take a look at Garry's Mod Workshop and find interesting maps.

Say the secret phrase.
Secret phrase is bloxwich Chat opens with "Y" key by default.

Play with 10 friends.
Checklist for organizing a meeting for the Friendly achievement:

• Find 10 active Garry's Mod players and send them friend invites. You can find players in the game's discussions, in this group, and elsewhere.
  
• Write to each of these 10 players that you need help with the Friendly achievement, ask the player's time zone and when he'll be ready to help you. If he refuses, just remove him from friendlist and find another player.
  
• Personally, I recommend writing down the time zones of the players in an MS Excel spreadsheet or text file so you won't get confused.
  
• After getting 10 players, create a Steam group chat and add these players to the chat.
  
• In the group chat, write the date and time of the meeting of the players and wait for the consent of all the players. Be sure to write @all at the beginning of the message!
  
• Usually, players can allocate time for such meetings on weekends (Saturday, Sunday) in the evening, at night. If the players are not ready to meet at your scheduled time, then try to schedule another time according to the availability of the players.
  
• If in 1-2 days not everyone answered your message in the group chat, then write to the unanswered players in private messages. If they do not answer you in 1-3 days, then unfriend them and find replacement players as soon as possible.
  
• An hour or a couple of hours before the meeting, remind in a group chat about the meeting with the ping of everyone.
  
  
• There is another way to get this achievement, but I haven't personally tested it:
  
• Go to any server with 50+ players online.
  
• Send friend invites to all players on the server and wait for at least 10 players to accept your invite. If you are asked for what reason you added player, write to him that you need the Friendly achievement.

Open the spawnmenu 100,000 times.

• Open the Garry's Mod page in your library.
  
• Click on the gear → Manage → Browse Local Files.
  
• In the folder that opens, go to garrysmod → cfg.
  
• Open the autoexec.cfg with notepad, copy and paste this:

• Close the file and save the changes.
  
• Open Garry's Mod and start single player.
  
• Press O on your keyboard and wait 1-3 minutes.
  
• After you got the achievement, close the game and delete the pasted code from autoexec.cfg.

Start Garry's Mod 1000 times.

• Set the graphics settings to the lowest so that the game starts faster.
  
• Click on the gear → Manage → Browse Local Files.
  
• In the opened folder, create a .txt file with any name.
  
• Open your file and paste this:

SET DRIVE_LETTER is responsible for the name of your hard drive where Garry's Mod is installed.
SET GMOD_PATH is responsible for the path to the folder where Garry's Mod is installed.
SET /A TIMEOUT is responsible for the time in seconds after which Garry's Mod closes.
The settings of the above lines can be changed for yourself.

• Save changes and close the file.
  
• Change the extension of this file from .txt to .bat and run the file.
  
• After you get the achievement, close the file and delete it.

Play on the same server & map for 4 hours

Play on the same server & map for 8 hours



You can open the gm_flatgrass map and leave the game in the background, sleep mode or hibernation for 8 hours.

Remove 5000 things using the Remover tool

Spawn 1000 NPCs.
To get the achievement, you need to spawn NPCs through the spawn menu. The best NPC to spawn is a crow.

Eat 200 balls.
They're in the Entity tab. Press E on the ball to eat it.

Killed 1000 Baddies.

• Start a single player game, write the following commands in the console and press Enter:

• Grab RPG, type "givecurrentammo" (without quotes) in the console and press Enter.
  
• Press X on your keyboard 5-10 times and kill the spawned headcrabs.
  
• Repeat step 3 until you get the achievement.

Kill 1000 friendly NPCs.

• Start a single player game, write the following commands in the console and press Enter:

• Grab RPG, type "givecurrentammo" (without quotes) in the console and press Enter.
  
• Press X on your keyboard 5-10 times and kill the spawned NPCs.
  
• Repeat step 3 until you get the achievement.

Kill 1000 innocent animals.

• Start a single player game, write the following commands in the console and press Enter:

• Grab RPG, type "givecurrentammo" (without quotes) in the console and press Enter.
  
• Press X on your keyboard 5-10 times and kill the spawned crows.
  
• Repeat step 3 until you get the achievement.

Burst 1000 balloons.
Balloons can only be spawned with the Tool Gun (Q → Tools → Building → Balloons).

Spawn 5000 props.
To get this achievement, you need to spawn props through the spawn menu. The best spawn prop is the VendingMachineSoda01a.

Spawn 2000 ragdolls.
To get this achievement, you need to spawn ragdolls through the spawn menu. The best ragdoll to spawn is the Combine_Scanner.

Get a total of 10 likes on your addons in the Workshop

Get a total of 100 likes on your addons in the Workshop

Get a total of 1000 likes on your addons in the Workshop

Get 1000 likes on a single upload

The Mega Upload achievement can be obtained in two ways:

• Find any addon with more than 1000 likes, ask the addon author to make you the addon author to get the achievement.
  
• Create a worthy addon, like a port of a weapons from other games or a player model. However, 1000 likes can also be scored on a selection of backgrounds for the main menu.

Play 1440 minutes = 24 hours = 1 day

Play 10080 minutes = 168 hours = 1 week

Play 43829 minutes ≈ 730 hours ≈ 1 month

Play 525948 minutes ≈ 8766 hours ≈ 1 year

The game can be kept in the background while you are using your PC. The following settings will allow Garry's Mod to consume the minimum amount of resources of your PC:


To use them, open the Garry's Mod page in the library, click on the gear → Properties → Launch options and paste the settings into the field.

Play with Garry Newman (creator of the game) on the same server.
This achievement is currently impossible as he stopped playing Garry's Mod a long time ago and ignores all messages and emails.
If you have nothing to do in your life, you can try to "catch"[www.gametracker.com] Garry by regularly visiting the list of game servers

The most popular mode in Garry's mod at the time of writing this guide. Its meaning is that players are divided into two teams: hunters and props. The team of hunters must find props and kill them. Props will have to disguise themselves as different objects to avoid being killed. Due to its simplicity, this mode is perfect for group gatherings in the game.
https://steamoss.com/sharedfiles/filedetails/?id=135509255

The second most popular mode in the Garry's mod workshop at the time of writing this guide. In this mode, people are divided into two roles: Murderer and Innocent.
The murderer must kill everyone and the innocent must collect clues to get the revolver and kill the murderer. Once there is a suspect in the murders, the innocent will have to shoot him. If the suspect was innocent, then the shooter dies, and a revolver falls from his body, which can be picked up by another innocent person. The process is repeated until the murderer dies or all the innocents die.
https://steamoss.com/sharedfiles/filedetails/?id=187073946

The essence of this mode is that people are divided into two teams: zombies and survivors. The survivors must survive and barricade themselves against the zombies, and the zombies must infect all the survivors. There are several different zombies with different abilities to choose from to defeat the survivors. The mode is interesting and can take a lot of time.
https://steamoss.com/sharedfiles/filedetails/?id=105462463

This is the most enjoyable of all modes. The idea is that on specially designated cards for this mode, people can launch videos and movies and watch them together. Nothing special, but the mode is quite entertaining.
https://steamoss.com/sharedfiles/filedetails/?id=118824086

The most famous mode is Garry's mod. It doesn’t really need a description, but will get a description nonetheless. On each server, players are divided into different roles and complete the objectives of the role. The whole process is built around people interacting with each other. It may well be exciting for people who are willing to spend most of their time in Garry's mod.
https://steamoss.com/sharedfiles/filedetails/?id=248302805

An interesting mode dedicated to the famous creepypasta character - Slender. Players are divided into two roles: Slenderman and his victims. The victims must collect the notes, and Slender must kill them. Nothing difficult or special, but very interesting.
https://steamoss.com/sharedfiles/filedetails/?id=171728689

A mode dedicated entirely to hide and seek. The most famous children's fun, which is now taking on a larger scale. My favorite mode because it asks you to think a little about where to hide and takes you back to childhood. Very similar to tag.
https://steamoss.com/sharedfiles/filedetails/?id=266512527

The mode is very similar to hide and seek, but more advanced. Now you will need to hide from the hunter among the NPCs and be like the NPC as much as possible, and the hunter must find you and kill you. Players have abilities on the side of NPCs that make life easier for them and complicate the life of hunters.
https://steamoss.com/sharedfiles/filedetails/?id=480998235

One of the basic game modes, available immediately. Dedication mode is identical to Murder mode, but with the difference that it's Murder on steroids. Absolutely every person has a weapon, which increases the degree of madness and the difficulty of calculating the killer. The principles remain the same. Who wants to identify the killer personally and personally, then this mode is just right.

The most popular of all the myths is Garry's mod, which appeared in Russia - meaty. According to him, a certain entity called “meat” lives on the gm_construct map. You can only summon it by killing many NPCs and after that he will appear and can even kill you.

It was found out experimentally that it doesn’t exist, but people don’t really care about it, so go for it.

And here’s what the author (Dochtúir Murtajë Neamhchothrom) imagines the meaty looks like while it’s waiting for you:

The next myth is the observer. In itself, it is old as the world and new as a phenomenon. According to him, on a variety of maps there is some entity that watches what you do.

Nothing supernatural, an explanation of this will be given further.

The following is rather a collection of various stories about the existence of a variety of shadow entities in the Garry's mod on different maps.

Searching for shadow people will not give much results - they disappear as soon as you look at them.
This phenomenon appeared due to the fact that people played alone for a long time on different maps and at some point became paranoid that they were clearly not alone there and that there was someone on the map besides themselves and began to see different phantoms.

The origin and purpose of the shadows is unknown, but people talk about accidentally seeing fragments of these entities.

Their existence has been repeatedly disproven, but people continue to believe in it.

There are also stories about a certain creature that lives in the sewers on this very old map of Garry's mod. Stories about him are fragmentary and inaccurate. There are reports that this creature is aggressive, others report that it just moves around and does not pose a threat to the player.

However, observation and exploration of the sewers did not bring any results, so whether this creature exists is unknown. It is believed that he doesn't exist.

There are also stories that in Garry's Mod 9 there was a virus that displayed GMan's stretched face on the screen when the map was launched and crashed Garry's mod itself. There are a couple of videos on the internet demonstrating the effects of the virus.

This myth itself is subsequently true. This is a script that played the sound of an infected player coughing and wrote the word "cough" into the chat many times. There was a myth that this virus could cause VAC ban, but this was never confirmed. It is believed that it may still pose a threat to players.

There is a story about how one of the players discovered a GMan following him, whom he did not spawn. Having flown up to him, the player went off the map into black oblivion, and then flew out. There is no mention of this anywhere else. What it was, no one knows.

https://steamoss.com/sharedfiles/filedetails/?id=3028149747