Hotondo Ijou Zettai Miman(1994)

Hotondo Ijou Zettai Miman

Rorigado gets a blast from his past when Kuma Yabusaka, his best buddy from junior high, walks into his classroom after a four year absence. Except that Kuma's now a cute diminutive schoolgirl! (It seems that after an accidental chemical spill in a laboratory Kuma turned into a girl).