Skolopendra

Skolopendra is one of Keto's sea monsters.

The Mark of Athena
Leo Valdez, as captain of the Argo II, forgets to turn on the ship's detection system from radar to sonar so that Festus can detect any nearby monsters. When he forgets to, one of Keto's sea monsters follows them and tries to capsize their ship.

It pushes Percy down the stairs using its tentacles, and wraooed around Piper's legs and tries to drag her overboard. A tentacle slams into Frank Zhang knocks him overboard.

It withdrew after it got a "mouthful of fire" when Leo Valdez and Hazel Levesque threw some test tubes of Greek fire into its mouth. Leo hears a muffled explosion of Greek fire and a green flash of light inside the monster's body.

Appearance
It is the length of the Argo II, which is 200 feet long. It looks like a cross between a giant shrimp and a cockroach, with a pink chitinous shell, a flat crayfish tail and millipede-type legs. It's face is a slimpy pink like an enormous catfish with two glassy dead eyes and a gaping toothless maw. It has a beard, which has a numerous amount of tentactles sprouting from each nostril.

Percy describes it as "Shrimpzilla".