The Nemean Lion is a monstrous lion, born to the titan Typhon Typhon and mother of monsters; Echidna. In some myths the Nemean Lion was the son of the titaness Selene and Zeus. It lived around Nemea and terrorized the nearby villages, often killing the cattle and sheep. It lived inside a cave with two entrances.
The Nemean Lion possessed two characteristics which made him a powerful foe:
First, his skin was invulnerable to any weapon, melee or ranged.
Second, he was larger than a regular lion
As part of his famous labors, Heracles was tasked to kill the Nemean Lion, which no weapon could kill. Heracles shot the beast with arrows. Since they had no affect the Lion did not even notice them, aside one which fell before him. The Lion charged the demi-God after seeing the arrow, and Heracles hit his head with a club made of oak. The weapon temporarly blinded the monster yet shattered to pieces. Half blind and suffering from vertigo the Lion retreated into its cave. Heracles blocked one of the two entrances, rushed inside and suffocated the beast to death. From that point on, he wore the Nemean Lion's skin as a mantle, protecting it from harm.