|“|| We swear! Stealing from people is our specialty! I love harassment! Where are we going?
–Passalos and Akmon, swearing to slow down the Romans
The Kerkopes (also spelled Cercopes) are two brothers, Passalos and Akmon. They were turned into monkeys by Zeus due to their constant thievery. They are encountered by Leo Valdez and the crew of the Argo II in The House of Hades.
In Greek mythology, the Kerkopes were the children of Oceanus and Theia. Growing up, they were warned by their prophetic mother to beware a "Black-Bottomed Man." They became thieves, until Hercules caught them trying to steal from him. He tied them to a pole and carried them behind him. They were forced to look at his bottom, which had turned black from sunburn and dirt. He was the 'Black-Bottomed Man' that their mother had warned them about. He eventually let them go because they made really funny jokes. Zeus then turned them into monkeys.
The Kerkopes have set up shop in Bologna, Italy. When the Argo II docks there, they attack the ship and rob it, taking things like Archimedes' sphere and Piper McLean's dagger, Katoptris. Leo Valdez and Jason Grace chased after them, determined to get their stuff back.Leo tries to get it, but is stripped of his pants and wears only underwear ( later in the island of calypso he is in front of her with only underwear).At the Fountain of Neptune, they incapacitated Jason by trapping him in a net. Leo chases them to their hide-out and defeats them with a home-made flash-bang grenade. He then got their possessions back and agreed not to kill Passalos and Akmon on the condition that they go to New York and disrupt the Romans in order to slow down their attack on Camp Half-Blood. They dive under Leo and steal his pants.
Octavian mentioned he wanted them properly terrified before sending them to Tartarus.