MUSH

A MUSH, commonly known as a "Multi-User SharedHallucination", is a text-based online environment with its roots in Interactive Fiction. However, the title MUSH, like MUCK, is a pun on MUD (Multi User Dungeon), and rather good backronyms suggested by The Other Wiki also include Multi-User Shared Hack, Habitat or Holodeck.

Progressing down the text-based online game 'system reliance' scale from MUCKs, MUSH games are usually perceived as having the least systems support for roleplay. Whereas a MUD will usually provide players with an entire game's worth of systems to play with, roleplay or otherwise, and MUCKs offer their players systems comparable to those of Pen&Paper RPGs, a MUSH will often merely be a series of rooms, and only enough systems to allow players to communicate with one another in various ways, along with the occasional currency system. In other words, MUSH games generally encourage and trust their players to create and manage their own roleplay.

Tropes common to MUSHes

 * Alternative Character Interpretation: Quite often, where non-original/feature characters are concerned.
 * Just about everything on the Creator Standpoint Index applies to a MUSH at one point or another, whether you're talking about players and characters, or the staff and the MUSH itself.
 * Crossover: Sometimes happens.
 * Massive Multiplayer Crossover: Often the result.
 * Ultimate Showdown of Ultimate Destiny: The logical conclusion.
 * Mega Crossover: When people really get creative.
 * Fan Fiction: Essentially, in the case of MUSHes without their own, original setting or that allow for elements from other settings.
 * Original Character: MUSHes are usually divided between original settings (often requiring original characters) and settings based on pre-existing franchises (which often allow original characters, too).
 * The Wiki Rule: In more modern times, this has increasingly become the norm for existing and startup MUSHes.

Notable MUSHes, past and present

 * Akashat: An original setting, adult-roleplay MUSH. Noteworthy due to its firm focus on continuity, in-depth roleplay and complex storylines. Does not allow non-original characters.
 * Castle D'Image: Quite an old MUSH set in an original fantasy setting. Defunct.
 * Champions MUSH: Uses the Champions system of developing and playing your own superhero.
 * Elendor: The oldest, biggest, and longest-running Tolkien-themed MUSH, founded in 1991, set shortly before The Lord of the Rings. Had a huge membership when the movies came out, but has since dwindled.
 * Equestrian Dawn: A relatively new MUSH based on the popular My Little Pony: Friendship Is Magic television series. Quite active, although some bugs due to significant amounts of custom code work and ongoing development.
 * Endless City MUSH: A cross-genre superhero MUSH (which permits almost everything), set in The City, a location that exists outside of time and space, that's connected to every universe, and every time ever. It's easy to get in, and easy to leave, the hard part is finding Home again.
 * Heroes MUSH: Based on the Heroes TV series, with a similar approach to game-wide story arcs (Volumes), flashbacks and potential dystopian futures.
 * Mega Man MUSH: A rather long-standing MUSH based on the Mega Man games. Combines elements from almost all of the various series into one coherent setting, albeit by taking quite a few liberties with the canon time line. Has a website and wiki.
 * Multiverse Crisis MUSH: Huge crossover MUSH. Has all sorts of characters and themes crammed together more or less indiscriminately.
 * OtherSpace: One of the longest-running MUSHes (online since 1998), OtherSpace is self-described as a space opera/science fantasy interactive saga. Notable for having had 17 game-wide story arcs (plus hundreds of more localized ones) and for being willing to completely alter the structure of the game in order to keep the story going. Has a wiki.
 * Pokemorph MUSH: A place in the Pokémon world where Team Rocket experimented on fusing human genes to Pokemon. Most, if not all, of the results live on the island within the game. Notable for being the largest Pokemon-based MUSH still active.
 * Persona MUSH: This MUSH focuses on fusing the four main Persona games together in a coherent fashion, as well as adding shout outs to other games in the Shin Megami Tensei series. Also has a wiki.
 * Super Robot Taisen MUSH: Based on the Super Robot Taisen Original Generation games with basically every mecha series they could think of integrated, from the typical fare of Gundam and Macross to BattleTech and Xabungle. Has a wiki.
 * Videoland MUSH: Defunct. In its prime was a (slightly) more-serious take on its source material, expanding the cast to eight (and eventually ten) Gamemasters instead of just one.
 * Transformers 2005 MUSH: Longest-running and most successful Transformers-based game. Based on the original Transformers: The Movie. Running since Apr. 8, 1995.