Mares of Diomedes
Beautiful, deadly, and out of control, the four man-eating mares belonged to Diomedes, the king of Thrace. They even had names: Podagros (the fast), Lampon (the shining), Xanthos (the blond), and Deinos (the terrible).
For his eighth labor, Hercules set out to steal the mares. In one version, Hercules wasn’t aware that their madness was a result of eating human flesh. He left his companion, Abderus, to watch them while he fought Diomedes. Naturally, the mares ate the boy, so Hercules retaliated by feeding Diomedes to the mares.
Hercules then bound their mouths shut and presented them to Eurystheus, who dedicated the mares to Hera. He then sent the horses to Zeus as a sacrifice. Zeus refused the offering and sent tigers, wolves and bears after the mares to kill them.
Possible descendants of the mares include Bucephalus, Alexander the Great’s horse, and horses used in the Trojan War.