What is the Buffy the vampire slayer episode about losing memories?

Answer 1

The name of the episode was "Tabula Rasa" where willow casts a spell to make Buffy forget that she was in Heaven and for Tara to forget that she was horribly upset about Willow's use of magic. The spell backfires and the whole Scooby Gang (and Spike) lose their memories.

Answer 2

The episode you're referring to is "Tabula Rasa" from Season 6. In this episode, a spell cast by Willow causes everyone to lose their memories, leading to confusion and chaos among the characters. The episode explores themes of identity, relationships, and the consequences of magic.