Slim is the neighborhood con artist. Slim also "used to be" a Slime monster from the Dragon Warrior games.
He helped Joel sell his Time Phones, but actually stole the idea and sold them by himself. He later tried to steal Phil's credit cards at his birthday party using Bullet Bill-like credit card tracker missiles. Yet again, he was seen trying to sell a special phone to Phil, as well as a "laser pen" to Brad, in Evil's New Groove. The phone ended up being just a Sega CD box. In Slim's Choice, he had Craig do some vocals for a record...which sold only 4 copies.
Slim was the first character to be erased by the time anomaly, followed then by Craig. They vanished into thin air during the intro of Bonus Stages due to Phil's meddling with the history of the show.