Nemean Lion

The Nemean lion (λιοντάρι της Νεμέας in Ancient Greek) was a monster in The Titan's Curse. It is known for being one of the beasts fought by Hercules. The Nemean Lion is one of the children of the faded Titaness of the moon, Selene and Zeus, which she bore on request of Hera and fell from the moon so the later could send it after Hercules. It is also said to have been the son of Echidna and Typhon or the offspring of Orthus and a chimera.

History
In Greek mythology, the Nemean Lion was a task given to Heracles by his cousin King Eurystheus. After hearing his description of the lion, he was able to confront it, and did not use any weapons at first; instead he wrestled it to death. When he tried to cut its skin, his knife shattered, eventually Athena told Hercules to use the lion's claws to skin it.

The Lightning Thief
While Percy, Annabeth, and Grover were on the train to do Denver, Percy was looking out the window when he saw a huge lion. He thought this was weird since there were no lions in America. When he was attacked by the Nemean Lion in The Titan's Curse, he recognized it as the lion he'd seen on the train.

The Nemean Lion was later depicted being defeated by Heracles during a firework display at Camp Half-Blood.

The Titan's Curse
The Lion was sent by Luke and the General at the National Air and Space museum to stop the group of questing Hunters and Demigods. It battled with Percy Jackson, but was hard to defeat because of its bulletproof and sword-proof pelt. Zoë Nightshade and Bianca di Angelo shot arrows into the Nemean Lion's only unprotected surface, it's mouth, which Percy exposed by throwing astronaut food into it's mouth. The lion dissolved except for it's pelt.

Spoil of War
The Lion's spoil of war was its pelt. Percy Jackson receives this when he defeats it, and Heracles (Hercules in Roman Mythology), in Greek Mythology received it as well. When worn, it still has the same abilities of it being bulletproof and sword-proof (invulnerable to damage). In the modern day, the pelt takes on the appearance of a full-length golden brown coat, but for Hercules he wore it as a lion's coat and it became his identifiable look.

Appearance
The Nemean Lion was the size of a pick-up truck, with silver claws and golden glittering fur. It's fangs gleamed like stainless steel.

Trivia

 * The Nemean Lion terrorized the kingdom of Nemea, hence it's name.