Ranma ½: Season 0, Episode 7

0 - 7: Stormy Weather Comes to School! Growing Up With Miss Hinako

A new teacher arrives - Miss Hinako, a peculiar young girl capable of draining people's energy, turning herself into a sultry 20-something in the process. Seeing her take out Happosai with one blast, Ranma desperately wants to learn how she does it.