 This movie was a variation on one of the episodes in the  _"Urusei yatsura" (1981)_ (qv) TV series. In that episode, Ataru is  sleeping during class, and keeps saying things in his sleep that  enrage Mendou. meanwhile, his dreams turn out uniformly bad, thanks  to Mujaki, who is trying to keep Baku fed. Therefore, he offers  Ataru nightmare after hideous nightmare, until Ataru finally  browbeats him into giving him the "harem" dream that appears in this  movie.