In Ovid's Metamorphoses, Phantasos was one of the sons (triplets, sometimes simply the most prominent three of many) of Hypnos (god of sleep) and Pasithea (goddess of relaxation, meditation and hallucinations) or Nyx (goddess of night) and Erebus (god of darkness).
Phantasos' brothers/fellow Oneiroi are Morpheus (who excels in presenting human images) and Ikelos (who presents images of beasts, birds and serpents)
Phantasos was the God of surreal dreams; he represents the inanimate objects seen in Prophetic dreams, images of earth, rock, water and wood.
Phantasos governs good dreams, but usually his dreams are a little cryptic. The word, Fantasy, comes from his name. Phantasos often takes the form of a woman since his dreams usually deceive people.