Guab is the alien pet of Aunty Gravitee and the guard of her prisoners who have to participate in her freakshow.
He can't talk and is very small. He has a yellow skincolour and a round shape. When he has to tackle someone he grabs the person in his mouth and spits him out. His vomit is very strong where even Robotboy couldn't escape from it in his normal mode when he was eaten by Guab.
When Gus and the other aliens escape, they capture Aunty Gravitee and Guab.