Morpheus ("he who forms, shapes, molds") is the principal Greek god of dreams. His father was Hypnos, god of sleep. Morpheus had the ability to take any human's form and appeared in dreams as your loved ones. His brothers Icelus, Phobetor and Phantasos were the other Oneiroi. He was mentioned in the Metamorphoses of Ovid and lived on a bed made of ebony in a dark cave decorated with poppy flowers.

The drug morphine derives its name from Morpheus based on its similar dream-inducing power.