In Ovid's Metamorphoses, Phobetor ('Frightener'), so called by men, or Icelos ('Like'), so called by the gods, is one of the thousand sons of Somnus (Sleep). He appeared in dreams "in the form of beast or bird or the long serpent".

What is Phobetor?

Phobetor meaning

Filters. (Greek mythology) The god and personification of nightmares; a son of Hypnos and Pasithea, or Nyx and Erebus.

Is there a Greek god of nightmares?

In Greek mythology, Epiales (Ancient Greek: Ἠπιάλης) was the spirit (daemon) and personification of nightmares.