According to the good people at the Pergamon, the Sirrush (Der Muschchuschu, or "splendor serpent") "...is the symbolic animal of the Babylonian patron deity Marduk.* The three-dimensional relief portrayal of the dragon is to be found on the gate of Ishtar of Babylon which was erected in the early 6th century by King Nebuchadnezzar the II.
The mythical creature is composed of a reptile's body, the head of a horned viper, the front paws of lion, the hind leg of an eagle and the tail sting of a scorpion."
Sorry chimera, I think I have a new favorite mythical animal.
*wikipedia notes that his specialties included "water, vegetation, judgement, and magic." Useful sort of fellow.