Rat

These enemies are pretty harmless, and are found in many dungeons.

Wind Waker
Give them All-Purpose Bait, and they'll share some of their treasure with you; Don't, and they'll take some of yours. While holding bombs, they're called Real Bombchus.

Twilight Princess
They are vile pests that can be found in caves or in the Arbiter's Grounds feeding off of skeletons. They also have a Twilight version called Twilight Vermin and have a squid-monster-like look to them.