The Hydra Claw is a pre-Hardmode enemy that spawns in the Surface during the Night, as well as in The Mire during the Night. It acts similarly to the Demon Eye, with the exception that it inflicts Poisoned when it hits the player. It has a counterpart called the Dragon Claw that is themed after The Inferno. The Hydra Claw drops Hydra Claw items, which are necessary to craft the summoning item for The Grips of Chaos.
The Grips of Chaos also can summon a stronger version of Hydra Claws during their boss fight.