In Classical Greek mythology, the Chimaera (also spelled Chimera) was a beast that consisted of the head and body of a lion, with a tail that morphed into a venemous serpent's head and the head of a goat springing from her back. The Chimaera could breathe fire from her lion's head. In some versions of the story, the snake sprung from the lion's shoulders next to the goat head, and in other versions the snake is replaced with a dragon's head.
The Chimaera was born from the unholy matrimony of the monster Typhon and its mate, Echidna, and had Cerberus, Hydra, the Nemean Lion, the Sphinx, Ladon, and Orthus as siblings. (In some versions the Sphinx was the daughter of the Chimaera.) The Chimaera is thought to have participated in the battle against the Gods with her parents and siblings, and was spared from the wrath of Zeus' thunderbolts because she could pose a challenge to future heroes.
The Chimaera ravaged and terrorized the kingdom of Lycia for years, until eventually she met her match in the hero Bellerophon riding the winged horse Pegasus. In some versions of the story, when the Chimaera opened her lion's mouth to breathe fire, Bellerophon shoved a spear with a lump of lead on the end into her gaping maw. The fire quickly melted the lead, and it made its way into her stomach and killed her.
The name 'Chimaera' comes from the Ancient Greek for 'she-goat'.