Final answer:
In Greek mythology, Medea kills her rival and the king of Corinth by poisoning them with a robe and diadem that burn them to death.
Step-by-step explanation:
Medea, a figure from Greek mythology, is known for her tragic and violent acts. In her most notorious deed of vengeance, Medea kills her rival and Creon, the king of Corinth, in a gruesome manner through poisoning. She sends a poisoned robe and diadem that, once put on, cause the wearers to die agonizingly as the gifts consume them in flames. This act is a culmination of her wrath towards her ex-husband Jason who has betrayed her for another woman.