Pizza Rat is a character in "We Bare Bears: The Movie". The Pizza Rat is among the many internet animal celebrities seen in the party. He is often mocked by the other animals for wanting to desperately get more likes and followers. He is even shown to have a rivalry with other imitators like the Spaghetti Rat, stating that he will end him in a threatening manner.
Later on, Pizza Rat literally ratted out the Bear's location to Agent Trout and his troops in a selfish act to get more followers. Afterwards, Pizza Rat's status is left unknown, though it is likely possible that he was kicked out of the party after his treachery was found out, therefore becoming an hated and losing his followers that he'll never deserve any chances for good.