Tantalus

Tantalus (Ancient Greek: Τάνταλος) was a mortal king who was sent to the Fields of Punishment for his sins. He also served as temporary activities director of Camp Half-Blood during the events of The Sea of Monsters. He will be played by Mark Hamill in the film.

History
Tantalus was the king of Tantalis, an ancient western Anatolian city named after him. 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.

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 away.

The Sea of Monsters
Tantalus replaces Chiron as Camp Half-Blood's activities director for a time when Chiron is suspected of poisoning Thalia's tree. He doesn't like the campers and appeared to take particular pleasure in torturing Percy Jackson and his half brother Tyson. He seemed to have a soft spot for Clarisse 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 dessert for a week.

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.

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.
 * The element Tantalum, and the mineral Tantalite are both named after Tantalus.