Orthus 
 
Orthus was the two-headed hound of Geryon. Orthus 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 owner of large herds of the white cattle. Geryon had Orthus to guard his prized cattle. Heracles killed Orthus and Eurytion, Geryon's herdsman, before driving the cattle back to Greece.