Cottus

Cottus was one of the three Hekatonkheires (Hundred Handed Ones), also known as Striker and the Furious.

History
Cottus helped the Olympians in the First Olympian War by throwing hundreds of rocks at the Titans after Zeus freed them from Tartarus. He faded away, along with his brother, Gyges, after humans forgot who he was and his story, leaving only their brother Briares.

The Battle of the Labyrinth
Cottus is mentioned by Briares, his brother, when talking to Percy, Annabeth, Grover, and Tyson in the Labyrinth.

Trivia

 * His name means 'The Furious' in Ancient Greek