Trouble Chocolate(1999)

Cacao, a student at Micro Grand Academy, wakes up one morning to find a girl made of wood sleeping in bed with him. She is Hinano, a tree spirit who possessed the body of a wooden puppet after Cacao messed up his magic teacher's spell. Having taken an instant liking to Cacao, Hinano enrolls in his school. Between Hinano, monsters, two strange twins and their four-eyed cat master, a demon boy, odd teachers and students, and the fact that he may have the potential to be one of the greatest magic users of all time, Cacao's life seems to have taken several turns for the worse...and the weird.

(Source: Anime News Network)