Leo Valdez, as captain of the Argo II, forgot to turn on the ship's detection system from radar to sonar so that Festus could detect any nearby monsters. If he had done that, the Skolopendra's arrival wouldn't have taken them by surprise. When it arrived, the Skolopendra tried to capsize the Argo II.
Before Percy could fight it, the Skolopendra pushed the son of Poseidon down the stairs using its tentacles, then wrapped around Piper McLean's legs and tried to drag her overboard. A tentacle slams into Frank Zhang, knocking the centurion overboard.
It was the length of the Argo II, which was two-hundred-foot-long. It looked like a cross between a giant shrimp and a cockroach, with a pink chitinous shell, a flat crayfish tail and millipede-type legs. Its face was a slimy pink like an enormous catfish with two glassy dead eyes and a gaping toothless maw. It had a beard, which had a numerous amount of tentacles sprouting from each nostril.
- According to some myths, the Skolopendra was the largest sea monster.
- Its name means "centipede" or "millipede" in Latin.
- Scolopendra is the name of a genus of centipede.