Tantalus was the king of a city, Tantalis, which was named after him. Zeus offered him a spot at the Olympian's table. But when he went to them, he stole nectar and ambrosia, brought it back to his people, and revealed the secret of the gods. For 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 the boy's 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 by Hephaestus.
However, because of the theft when Tantalus died, his punishment was stand in the middle of a lake under the branches of a fruit tree. But whenever he reached for the fruit, the branches would retreat from his grasp. Whenever he leaned down for a drink, the water would recede from him.