The Crummy Mattress

The Crummy Mattress was found in the corruption by Cyril so that it could be used as a joke in the comic and because Cyril wanted to sleep on something different. June wondered several times why he kept it.
-I've slept enough tables in my time to know the value of a crummy mattress.
Cyril, comic #191
Hannah can be seen sleeping on the crummy mattress in comic #320.