a creature from Kurt Vonnegut's book "Sirens of Titan". The Harmoniums are first introduced in chapter 8. They live in caves on the planet Mercury. The Harmoniums feed on the vibrations of the planet's song, have in fact been feeding upon a single note of that song for centuries.

Harmoniums are a creature that exists in a Utopia specific to them. They have no fear, no hunger. Indeed, they have none of the negative qualities that shape our lives.