The giant shepherd tried to fight back, but Hercules easily killed him with his great club. Right after that, the hero was attacked by a malevolent looking two-headed dog, Orthros. Hercules had to defend himself from its attack and he then proceeded to subdue the bizarre animal with his club. Promptly, the hero gathered the oxen and he was ready to lead them back to his ship, when Geryon himself arrived at the pasture. "I am Geryon, the son of immortal Chrysaor and Kallirhoe. You, a mere mortal, dare to challenge my power and authority on the soil of my own island?"
The giant looked fearful, possessing three bodies and three heads combined into a single disfigured entity. His three heads were reddened with fury at the hero’s insolence. He attacked Hercules and the hero found himself at a disadvantage; his enemy's strength was this time greater than his own. The son of Zeus ran and readied his bow as the giant followed him with leaps and thrusts. As Geryon was about to grab him, the hero turned around and shot one of his poisoned arrows right into one of the giant's foreheads. The poison of the Hydra rapidly made its way through the three heads of the giant and left him dead in his tracks.
His great body collapsed to the ground. Hercules took a look at his fallen enemy, making sure he was no longer a threat. He then gathered the flock once more and led it to his ship. He was grateful that the gods had let him best such a powerful enemy. At dawn, the hero and his herd left for Peloponnese. After another year of travel, as the Hercules stepped on solid ground once more, he felt a need to rest.
While he was caught in a deep sleep, a thief called Cacos stole a large part of the flock and led them to his cave. Hercules realized that this spelled failure to his endeavour; he tried to track down the animals but to no avail, because the cunning thief had made them walk backwards to cover their trail. Heavyhearted, Hercules decided to continue his way to Peloponnese with the flock he had left. But upon passing by a certain cave at the Tyrrhenian countryside, he heard discontent oxen voices from its depths. Soon the oxen of his flock started responding to those voices and the hero realized that the missing oxen were being kept in that cave.
Hercules was repulsed by the sight of human heads nailed around the gaping chasm that was the cave’s entrance. As he made his way to it, a huge boulder fell and Hercules took a step back to avoid being crushed under its weight. The entrance was now blocked and the voices of the oxen inside could now barely be heard. Furious at his adversary’s sinisterness and audacity, Hercules climbed on the rock that covered the cave and tore it apart. As the inside of the cave was uncovered, Cacos spewed fire and smoke towards the hero.
Hercules evaded his attacks and jumped down at the thickest of the smoke, landing on Cacos’s body. The two wrestled for some time and the son of Zeus finally prevailed, strangling his enemy with his powerful hands. The people of the land deeply thanked the hero for killing the monstrous tyrant who had claimed so many lives. Hercules continued on his way and when he made his way back to Tiryns, King Eurystheus deemed the Labor complete. He then proceeded to offer the oxen as sacrifice to Hera, as the oracle had instructed.