Wishverse

Even though the later episode 'Doppelgangland' (Buffy 3.16) suggests that the 'Wishverse' exists parallel to the Buffyverse and that characters can move from one parallel universe to another by magic, none of the characters except vengeance demon Anyaka can remember anything about the other world.

In the Wishverse, many of the good characters have been turned bad or are dead.

Whedon couldn't resist the pull of the Wishverse either.