Konna Panic(1991)

Konna Panic

Mai Kisaragi was born as a shy, and cowardly person; always allowing people to take advantage of her. The object of her affection is the school's basketball star, Takumi Kai. This is where the story might have begun and ended... if something strange hadn't happened. Tired of being mocked one day, she suddenly gains a supernatural power during basketball practice. And soon, she is visited by a fox spirit named Ran who informs her that she is, in fact, a ​part fox spirit. At first, she doesn't believe him... until she transforms into a fox herself.

(Source: Anime News Network)