Shadow Vermin

Shadow Vermin are enemies encountered in Hyrule Castle Sewers after first being transformed into Wolf Link and escaping with Midna. These are not to be confused with the Ghoul Rats found elsewhere. They are possibly rats that were transformed by twilight.

Characteristics and Weaknesses
Shadow Vermin appear as small, black, squid-like creatures which attack by flailing randomly at Link. Fighting them can be tricky, as they will attack while swimming across the water, and can sometimes be hard to spot until they get very close. They are quite fast, and can attack when least expected.

Shadow Vermin also make an appearance within the Palace of Twilight. The only difference is there is no water for them to skim across.