Tantalus was a mortal king in Greek mythology. He did many bad things against the gods and goddesses. At a banquet, he tried to feed people the flesh of his son Pelops. He had asked the gods and goddesses to come to this banquet. When they learn what he had planned, they punished Tantalus in not only this world (the world of the living), but the next as well (the world of the dead). Tantalus's punishment while he was alive was the ruin of his kingdom. His punishment when dead in the Tartaros of the Underworld was much worse.
He was made to stand in a pool of water up to his chin for all time. During this, he would always be hungry and . Each time Tantalus lowered his head to drink the water he was standing in, the water would lower. Over his head hung branches of trees filled with fruit. When he would try to get them, wind would blow them out of his reach. He was "tantalized" with food and drink. This is where the word tantalize comes from.