Orthus

Orthus was the two-headed hound of Geryon. Orthus (Ὄρθρος) was the monstrous offspring of Typhon and Echidna. Orthus was probably the father of the Sphinx, by Echidna.

Geryon was the king of Erytheia (Cadiz) in Spain, and the owner of large herds of white cattle. Geryon had Orthus guarding his prized cattle. Heracles killed Orthus and Eurytion, Geryon's herdsman, before driving the cattle back to Greece.