Ghoul Rat

Ghoul Rats are found in spooky environments such as the Arbiter's Grounds and Hyrule Castle in Twilight Princess. They are normally invisible and they use that advantage to cling on to you and slow you down, but to the sharply "sensed" animal, these rats are easy pickings. When the rats are on you, turn into your wolf form and activate your senses then do a spin attack to wipe them out. In human form, Link will start walking as if he had the Iron Boots on. When in wolf form, you'll know their clinging to you by seeing Midna panicking or you start walking slowly. They don't inflict damage while attached, but the decreased speed can hinder progress greatly.