Alternate Reality Episode
An Alternate Reality Episode is slightly different from an episode that incorporates an Alternate Reality
In an Alternate Reality Episode, the usual main characters are absent. The main cast is still here, but they're playing "themselves" in a different role. Maybe Alice is now a Dot Com boom millionaire instead of a lowly research assistant, or the other way around. The point is that it's our heroes being different people, not the same people visiting a different place.
Typically, the "normal" situation may get a look-in for a couple of scenes at the start or end of the episode, but there should not be any clear link between the characters - Alice the millionaire should not wake up as Alice the research assistant, or have Bob her millionare buddy visiting her, asking why everything is different.
Compare with Parody Episode
(this trope could be considered the serious side of the coin) and Elseworld
. This may be a Mirror Universe
episode where we see what the cast would be like if they were evil
(especially in Star Trek
- Mirrored, the IDW comics' New-Trek-Movieverse version of "Mirror, Mirror" had more in common with Star Trek: Enterprise's "In A Mirror Darkly" than the Original Series episode. It opens and closes with "our" Scotty and McCoy discussing the concept of alternate universes, and the rest of the story is set entirely in the Mirror Universe, with no "real" characters. (Well, Old Spock seems to have come from [a version of] the regular universe rather than the mirror one, but he's still not the same Old Spock.)
- The Powerpuff Girls was to have an alternate reality episode, "Deja View," half of which was supposed to be in CGI, but it went over budget and was facing a tight deadline. The original story outline was given to DC Comics for issue #50 of the PPG comic book. It had the girls sucked into a vortex and winding up in Townsville's alternate counterpart Viletown and the girls' alternate counterparts, the Powerpunk Girls rending Townsville asunder.
- The Fairly OddParents have done this a few times. Examples include the episode Timmy wished everyone was part of an action movie, with Timmy as the buff hero, Jorgon as the villain etc. and The Big Superhero Wish were everyone in town becomes either a comic book hero or villain.