Rex is a large turquoise worm with yellow eyes. He wears a black collar. Rex pants and barks like a dog, like all worms in the series.
Role in series
Rex ironically leaves on the bus after SpongeBob praises his loyalty. Rex was only bought in an attempt to make Gary jealous and realize that he should return to his former master. The only trick he can do is "stay." He did not stay for long, considering the fact that he left almost immediately after he went to the bus stop. Afterward, Spongebob gets another new pet and says to himself “Who needs worms anyway?” and it is unknown where Rex went.