Grotesque e no Shoutai

Yusaku, the son of the village police station, meets a young girl named Neri on the beach and becomes friends with her. However, she has a terrible secret. If she says "I love spiders", she becomes a spider, and if she says "I love lizards", she becomes a lizard...

Note: published in Gekkan Shounen Jump 1981/09 and later compiled in volume 7 of Tiger Books