– Reyna's silver Automaton hound who appears in The Son of Neptune, The Mark of Athena, The House of Hades and The Blood of Olympus. Aurum – Reyna's gold Automaton Hound who appears in The Son of Neptune, The Mark of Athena, The House of Hades and The Blood of Olympus. Celedon – Automatons forged by Hephaestus to serve as Apollo's backup singers. In Percy Jackson and the Singer of Apollo, Percy Jackson had to find the fourth Celedon for Apollo after it left Mount Olympus and fled into Times Square. Colossus of Nero – A gigantic automaton built under Nero's orders in the images of Apollo and himself. Nero uses the statue to invade Camp Half-Blood in The Hidden Oracle. The Colossus proceeds to destroy the Dining Area and Demeter's Cabin before being infected with Apollo's hay fever plague arrow and subsequently decapitated. The headless statue is then given to Poseidon to be repurposed, likely into a statue of Poseidon himself. Mechanical Spiders – A bunch of automaton spiders that were created by Hephaestus. Talos – Talos is a giant automaton. Percy, Thalia, and Bianca fight a prototype of Talos in the Junkyard of the Gods. Apparently, he has a manhole at the base of his foot for servicing. Bianca went in to mess up his circuit so they could defeat him. He fell on some power lines thus electrocuting Bianca. Basilisk – Fire-breathing snakes with colorful spikes and poisonous bites. In The Son of Neptune, they attacked Camp Jupiter, but Frank shapeshifts into a mongoose (or weasel) and scares them off. Buford – A walking table that Leo Valdez saved from a supply closet and prefers to be polished by Lemon Pledge instead of Windex. He assists Leo Valdez in constructing the Argo II in Bunker 9. Eventually, Leo programs a talking mini-hologram of Gleeson Hedge onto Buford. Carthaginian Serpent - A 120 ft. serpent. In The Dark Prophecy, Apollo, Meg, and Leo face this monster while making their way to Commodus' lair. Apollo tricked it into crashing into a nearby condemned condominium. Centicore – Deadly antelope-like creatures who guard the Cave of Trophonius. Due to their endangered status, Apollo goes to great lengths not to kill them as he soaks himself in the waters of Lethe and Mnemosyne. Cerberus – The three-headed dog who guards the entrance to the Underworld. In The Lightning Thief, he befriends Annabeth.