Grindylows are a fictional sapient species featured in the Harry Potter series.
Grindylows are small humanoid creatures who dwell in the weed beds of lakes and rivers in Great Britain and Ireland. They have pale green skin, long fingers and sharp horns and teeth; in the films, they are also shown to have eight tentacles instead of legs. Grindylows mostly survive on a diet of fish but some have been known to eat humans who had fallen into the water. Grindylows are sapient and are subservient to the more intelligent and culturally developped Merpeople.