Wimp on the Barby is episode 43a of Rocko's Modern Life. In this episode Rocko prepares for a visit from his grade-school bully, Dingo.
While Rocko is mowing his front lawn, Spunky sneaks up behind Ed while the toad is trimming his hedges. Annoyed, Ed calls for Rocko and berates him. Bev, however, yells at him, tells him to get back to his yardwork and gives Spunky back to Rocko. She also tells Rocko that he needs to learn how to stand up to her husband, to which Rocko responds that he's not good at confrontations.
Meanwhile, inside Rocko's house, Heffer and Filburt are watching television when they hear the telephone ring. Heffer answers it and feigns an Australian accent while talking to Rocko's mother. When Rocko comes in the house, Heffer tells him that Dingo is coming over to visit him on Saturday, much to Rocko's horror as he freaks out. Rocko tells his best friends about the bullying he has suffered from Dingo ever since he was in 3rd grade in his native country Australia right before he left to America.
During the early morning, Heffer and Filburt wake Rocko up by surprise and Heffer has Rocko running around his house while constantly blowing his whistle, which Bev later snatches from him after coming outside to stop the loud noise. So Heffer replaces his whistle for a tooter and has Rocko do thirty push-ups. But the wallaby only manages to do just one and he attempts to leave to circumvent an impending fight. But Filburt holds him back and he and Heffer give Rocko lessons on preparing himself to face his childhood bully. They train him to turn into a "savage blood-thirsty beast" and their methods has turned Rocko into a monster. During the night, Rocko stares at the poster of the beast Heffer showed him earlier, tears off the face, and puts it in his mouth. As he chews and swallows it, Heffer and Filburt, having been watching from the car, can now see that Rocko is prepared.
The next day, Heffer and Filburt hide as someone knocks on the door. When Rocko answers it, he finds Dingo, who has had his ears cut off and he is now known as "Foofy No-no." He reveals that he is a member of the Hare Krishna-esque group of unicorns and is now at peace with everyone. He also offers Rocko various gifts as his way of saying sorry for being mean to him when they were kids and asks him to punch him in the nose as payback for the bullying he has done. Rocko, however, is hesitant and feels that violence won't solve anything, for it would only make things worse. But when Dingo asks him a second time, Rocko complies and punches him square in the nose. As Dingo walks away, Heffer and Filburt, oblivious to Dingo's changed personality, attack him by surprise and Rocko, inside his house, regrets his decision and discusses to Spunky how he isn't one to resort to violence.