Sqornshellous Zeta is a swampy planet, best known for its mattresses. One of those mattresses talks to Marvin, who is stuck in the ground due to a defective leg. Marvin tells the mattress about how he has come to be there, and his story includes how he once gave a speech when he was hired to open a bridge. When he had plugged himself into the opening circuits of the bridge, it folded up and sank into the swamp, with everyone who was on it.
Sqornshellous Zeta is a very swampy planet, often covered in mist. The dew, at least in Marvin's opinion, falls "with a particularly sickening thud" in the mornings. There are grey swamp trees and tall reeds on the surface of the planet. Every morning at sunrise, the sun looks small, cold and slightly damp, before it sinks fourteen hours later with a distinct feeling of hopelessness.
Sqornshellous Zeta appeared in chapter 7 of the Douglas Adams novel Life, the Universe and Everything. It seemingly deliberately defies the English language convention that 'q' must be followed by 'u'.