Tantalus

Tantalus (in Ancient Greek: Τάνταλος) was a demigod king who was sent to the Fields of Punishment for his cannibal actions against the gods. He also temporarily served as activities director of Camp Half-Blood during the events of The Sea of Monsters. He will be portrayed by Mark Hamill in the film adaptation of The Sea of Monsters.

History
Tantalus was the king of Tantalis, an ancient western Anatolian city he was named after. Zeus offered him a spot at the Olympian table and he accepted. When he went to them, he stole nectar and ambrosia, brought it back to his people and revealed a secret of the gods. In doing so, he offered up his son Pelops as food for the gods. Only Demeter touched the food because she was distraught about her daughter, Persephone. She didn't know what it was and ate part of Pelops' shoulder. Zeus took the parts of the boy, put them together, and was able to bring him to life once more. He was given a bronze shoulder made by Hephaestus. In another myth, he stole a golden dog, made by Hephaestus, and gave the dog to his friend for safekeeping and later denied ever seeing it.

For his terrible crime, Tantalus was subjected to eternal starvation and thirst. He was made to stand in a lake with a fruit tree growing on the shore with fruit growing on a branch above him. Whenever Tantalus tried to drink, the water dried away and when he wanted to eat, a strong wind blew the fruits out of his reach.

The Sea of Monsters
Tantalus replaces Chiron as the activities director for a time at Camp Half-Blood when Chiron is suspected of poisoning Thalia's tree. He seems to take particular pleasure when the campers realize who he is, and tells them a story about a mortal king who was beloved by the gods - himself. He doesn't like the campers and appeared to take particular pleasure in torturing Percy Jackson and his half brother Tyson, who is a Cyclops. He seemed to have a soft spot for Clarisse La Rue and was the one who decided to send her on the quest. He also started up chariot racing again with the warning that if anyone killed another person, they would have no smore's for a week.

When Stymphalian Birds attack the campers whilst they are watching the chariot race, Percy and Annabeth Chase decided to try and fight them off by using Chiron's boom box from the Big House. Clarisse tries to fight them unsuccessfully, but the birds are scared away by the noise of Chiron's collection of CDs and get shot down by the archers of the Apollo Cabin. Tantalus congratulates Clarisse on winning the race, but then punishes Percy and Annabeth for being trouble makers. In Tantalus' mind, the Stymphilian Birds were simply minding their own business until they were disturbed by Annabeth and Percy's bad chariot racing and awful music that they played, he assigns them to a week of kitchen duty.

While he was at the camp, Mr. D took particular pleasure in watching him try to eat or drink, always unsuccessfully. Just before he was sent back to the Underworld, he managed to pick up a burger, but before he could eat it, he was sent back to the Underworld after being dismissed by Mr. D.

Trivia

 * The word tantalize (meaning to tease or disappoint by promising or showing someone something desirable and then withholding it) derives from Tantalus, due to the nature of his punishment.
 * He was named after the city he was born in, Tantalis.