Tantalus was initially known for having been welcomed to Zeus' table in Olympus, like Ixion. There he is said to have misbehaved and stolen ambrosia and nectar to bring it back to his people, and revealed the secrets of the gods. Most infamously, Tantalus offered up his son, Pelops, as sacrifice. He cut Pelops up, boiled him, and served him up in a banquet for the gods.
The gods became aware of the gruesome nature of the menu, so they didn't touch the offering; only Demeter, distraught by the loss of her daughter, Persephone, absentmindedly ate part of the boy's shoulder. Clotho, one of the three Fates, ordered by Zeus, brought the boy to life again (she collected the parts of the body and boiled them in a sacred cauldron), rebuilding his shoulder with one wrought of ivory made by Hephaestus and presented by Demeter.
The revived Pelops grew to be an extraordinarily handsome youth, so much so that the god Poseidon fell in love with him and abducted him to Mount Olympus. Later, Zeus threw Pelops out of Olympus due to his anger at Tantalus. The Greeks of classical times claimed to be horrified by Tantalus's doings; cannibalism, human sacrifice, the mistreatment of guests, and infanticide were atrocities and taboo even in the brutal days of Ancient Greece.
Tantalus's punishment for his act was to stand in a pool of water beneath a fruit tree with low branches. Whenever he reached for the fruit, the branches raised his intended meal from his grasp. Whenever he bent down to get a drink, the water receded. As he was immortal for having eaten some of the gods' food at their banquets, his hunger and thirst are eternal. Over his head towers a threatening stone, like that of Sisyphus.
- The word tantalize, which means to torment and/or tease someone with the sight or promise of something unobtainable, is derived from Tantalus.