The Tenth Labour was to obtain the cattle of Geyron.
For this he had to reach Erytheia, an island in the mediteranean. The second he arraived Orthrus (a two headed dog) jumped on him but Hercules quickly dealt with him.
Not so far way Geryon heard the noise that had come from the dead dog and attacked Hercules. Seeing a giant with 3 spears and 3 shields running at him he shot a arrow at him, killing him instantly becuse the end had been dipped in the Lernaen Hydra 's blood.
He then herded the cattle and took it to King Erytheus.