Before he could pursue it, more dolphin warriors climbed the stairs, hauling up the rest of his friends. Jason was unconscious. Judging from the new bruises on his face, he’d tried to fight. Hazel and Piper were bound hand and foot. Piper had a gag in her mouth, so apparently the dolphins had discovered she could charmspeak. Frank was the only one missing, though two of the dolphins had bee stings covering their faces.
Could Frank actually turn into a swarm of bees? Percy hoped so. If he was free aboard the ship somewhere, that could be an advantage, assuming Percy could figure out how to communicate with him.

The Mark of Athena, Chapter XXX