gorgon in The Son of Neptune and fighting the Colossus of Nero alongside him in The Hidden Oracle. Hippalectryon – An endangered animal that is part chicken, part horse. In The Battle of the Labyrinth, they are seen at the Triple G Ranch. Hippocampus – Creatures that are horses from the waist up with a fish tail from the waist down. One is said to take a liking to Tyson, and he named it Rainbow. They are also called "fish ponies" by Tyson. Rainbow – A Hippocamus who befriends Tyson in The Sea of Monsters after being summoned by Percy for transport to the Princess Andromeda. He is stated to be bigger than most of his species and as such, has no trouble carrying a Cyclops on his back. Rainbow later rescues Tyson after the sinking of the CSS Birmingham and helps to carry Percy and his friends safely out of the Sea of Monsters after they get the Golden Fleece. When Tyson departs for Poseidon's palace, Rainbow gives him a ride. He is mentioned often following this by Tyson who maintains a friendship with Rainbow. In The Last Olympian, after Blackjack is stolen by Rachel Elizabeth Dare, Percy summons Rainbow for a ride to Camp Half-Blood. In The Blood of Olympus, Rainbow gives Tyson and Ella a ride across Long Island Sound to rescue Reyna, Nico and Coach Hedge from Roman demigods. He then carries Tyson, Ella and Coach Hedge back to camp. When Tyson explains to Reyna that he had reached the ship on Rainbow, Reyna is confused at first thinking that he is talking about an actual rainbow before Nico clarifies the matter. In The Tyrant's Tomb, Tyson has Ella give him a tattoo of Rainbow. Rainbow also appears in the Percy Jackson and the Sea of Monsters film. Incitatus - A talking white horse that wears golden horseshoes and is owned by Caligula. In The Burning Maze, Incitatus brings Apollo and Meg to Caligula. He later assists Caligula in fighting Jason and Tempest which ends in Jason's death. During the fight at the old Los Angeles Zoo, Incitatus and the Pandai that are with him are killed by the Meliai. Hydra – A serpentine monster with nine heads. Every time a head is chopped off, two new heads grow back. This monster appears in The Sea of Monsters where its life force is linked to the