This speculative fiction trope / comic book trope describes a story where the characters visit, get marooned in, or get visited by, another reality. It's kinda like a Dream Sequence, except it's real.
Alternate Universe types:
- Alternate History - Some major event changed, like Germany wins WWII.
- Another Dimension - Different worlds don't have to resemble each other, Alternate Universe is a subtrope of this.
- Bizarro Universe - A lot of things in that world are reversed from the usual context, good is evil or vice versa, etc.
- For Want Of A Nail - One small change caused a huge difference between the universes
- Mirror Universe - Often a subset of Bizarro Universe, Good and Evil are reversed, but otherwise most of the things are the same
- The Multiverse - The people involved have the capacity to cross over to more than one additional universe
- Elseworld - Famous character placed into a situation which potentially is wildly different
- Wonderful Life - You get to see how the world would have turned out if you were never born
Game and Story Use
- Adventure Seed: AlterWiki of Prague
- An alternate universe plotline is one way to really shake up the campaign for a session or two, without having tons of ramifications down the road. I mean, as long as the cross-over / dimensional gateway happened by mistake or due to a non-reproducable spacetime anomaly, you don't have to worry about what happens. You can kill off NPCs in the alternate universe, and they'll still be around when you get back home.
- At the same time, if every body really enjoyed it, there's some potential for the GM to revisit this plot device later.
- If your GM is particularly kind and generous, an encounter with an Alternate Universe might be a way to bring back a dead character. Or rather, a way to introduce a slightly revised parallel version of a former character. Just be aware that while All The Myriad Ways and Out of Time, Out Of Mind can be hand-waved on a show you passively watch for an hour a week, that sort of Fridge Logic might not hold up to the sort of scrutiny that RPG campaigns have to face.
- Personally, I wouldn't let a player get away with this unless they were specifically looking for the challenge of playing a really interesting new twist on the old character, and grappling with the complexities of being sucked into a world that is at once both familiar and alien.
- This may be more acceptable in a setting like Star Trek that already has a conflicting mish-mash of time travel and alternate universes in it's official cannon.