They have a peanut in the middle and a dollar sign next to it on each side. They come in ones but they may come in 5s, 10s, and greater amounts.
Role in movie
When Dennis attempts to to kill SpongeBob and Patrick on David Hasselhoff's leg, SpongeBob offers him the Goober dollars in an attempt to make him reconsider murdering them. After Dennis finds out that it is fake money, he throws them behind him and they fly into the wind.