Squirt has a similar appearance to Frankie, as they are the same kind of dog. Squirt is a lighter shade of brown than Frankie, has very large ears, and wears a plain red T-shirt. He's also shorter and younger than Frankie.
In the Game
In the opening cutscene, the destruction of his scooter by Jimmy Bumples motivates the other characters to win the competition so that they can give Squirt the Super Scooter that's the prize for winning. He also appears in the activity Frankie's Pizza Stand, acting as a waiter for Frankie's pizza business.