Knuckles, Vinnie and Kowalski are henchmen who worked for the Joker in Batman: The Animated Series. They are thugs employed by the Joker to take Mayor Hill hostage so they could activate an atom bomb in Gotham but it was foiled by Batman.
The Joker hired the thugs again to help him ruin the Laff-Off competition and get rid of the judges. The Joker and his henchmen subdued the host and took over the show. The henchmen were surprised by the Dynamic Duo's and were knocked out by Batman and Robin.