The Guest Who Betrayed the Table
Tantalus is a son of Zeus, favored enough to dine among the gods themselves, until — in the story told by Apollodorus and other later mythographers — he decides to test whether their knowledge is as complete as their power. He kills his son Pelops, cooks him, and serves the meal at a banquet for the Olympians. Most of the gods recognize the dish instantly and refuse it; only grieving Demeter, distracted by the search for her own daughter, eats a piece of the shoulder before anyone stops her, and the gods restore Pelops afterward with an ivory shoulder to replace what's missing.