Hydlings

A Hydling is a species in the GameCube video game Metroid Prime 2: Echoes. They are found only underwater, and are ultimately always found in large groups, where they travel the seas searching for anything that their small mouths can take in for food.

However, they're actually a powerful species, as their bite can go right through metal. They often times use this against any potential threat, including Samus Aran.