Eurystheus did not know that in giving these tasks he was making his cousin fulfil his course; but he was afraid of such a mighty man, and hoped that one of these would be the means of getting rid of him.  So when he saw Hercules at Argos, with a club made of a forest tree in his hand, and clad in the skin of a lion which he had slain, Eurystheus bade him go and kill a far more terrible lion, of giant brood, and with a skin that could not be pierced, which dwelt in the valley of Nemea.  The fight was a terrible one; the lion could not be wounded, and Hercules was forced to grapple with it, and strangle it in his arms.  He lost a finger in the struggle, but at last the beast died in his grasp, and he carried it on his back to Argos, where Eurystheus was so much frightened at the grim sight that he fled away to hide himself, and commanded Hercules not to bring his monsters within the gates of the city.