Beloved by the gods for his wisdom, the demigod Tantalus was once invited to their fellowship. Becoming boisterous whilst celebrating with them, he began to boast, and he stole the gods'' nectar and ambrosia, their food of immortality. When the gods came to see Tantalus in turn, he tested their omniscience by offering his own son Pelops to them as their meal. Offended by the deception, the gods banished Tantalus from their community to Tartarus and cursed him and his family, the House of Atreus. This became known as the curse on the Tantalids, in which descendants from Tantalus in every subsequent generation were driven by revenge and hatred to the killing of their own family members. (Excerpt from Wikipedia)
