For those who don't know, there exists a sort of multiplayer mode for Cataclysm called WatchCDDA. It's completely ASCII mode however, as it's played through the terminal.
It's not completely multiplayer due to how the game works (it would be too hard to get things to work correctly if players stood near each other), but you can watch others play and the world itself is shared, so if you for example die in a cabin, another player could technically stumble upon your corpse.
You can also watch others play.
There is also a Discord server for WatchCDDA found at https://discord.gg/HhuWWdW
The following explainations have been copied from the website:
Creating an Account
In order to create an account, enter in "ssh newacc@play.watchcdda.net -p 3333" into your terminal. The password is newacc. If you are on windows using putty, use newacc@play.watchcdda.net for host, and 3333 for port. It is worth noting that when you type passwords here, you won't see "*******" print to your screen - it will stay blank. It is still accepting input, just hit when you are done. Your username MUST begin with a lowercase letter. You will be disconnected after your username is chosen, and after you have successfully (or unsuccessfully) created your password. If you are unsuccessful creating your account or changing your password, log in and try again. Anyone who was playing when your account was created will need to reload their game for you to be able to watch it.
Logging in
For Linux/MacOS, type "ssh your_username@play.watchcdda.net -p 3333" into your terminal. For windows users, you should download Putty. Within Putty, select "ssh" and for Host, you can put in your_username@play.watchcdda.net. Port you should set to 3333. To select your options, type the number within brackets (and not the brackets). If you are ever confused what to do at a menu or need a description of the available options, you can always use "?" for a built-in help menu.
Playing
To play a game, select “play†and choose a game. Cataclysm Experimental is the regularly-updated experimental build oc CDDA, and Stable is 0.E. Cataclysm-Group is Experimental except that everyone who watches your game also has full control over it. This can be used to allow shared sessions. Cataclysm-Multiplayer is shared-world play. In this mode you can create a world and other people can play on it at once. You can NOT see their characters, but if you are both in different reality bubbles, you can drop items, clear towns, burn bases, etc. Things get weird when two or more players overlap reality bubbles (get too close in game at the same time). Best to try to avoid it. Cataclysm group / multiplayer have are described in more detail in the Developments page.