Bart is hailed as a hero when he stops a plot by Jimbo and his gang. But he becomes a target for everyone to destroy
Bart is on a TV show in which he is hailed as a hero for stopping a plot by Jimbo, Kearney, Dolph and Nelson to do bad. He's awarded a bulletproof vest by Chief Wiggum and Kent Brockman but he's warned that the bullies will get him for revenge.
Bart wears the vest to Marge's chagrin but it's effective as the vest stops bees and other attacks by Jimbo, Kearney and Dolph, however Nelson is left and manages to pin Bart but then a piece of the old monorail drops and Bart throws himself in front of Nelson to save his life. Bart is then awarded with an ax for his bravery by the Fire Department, Bart ditches the vest for his new "toy". Nelson does pay Bart a compliment for saving his life, and wonders about the vest, Bart doesn't think it's effective but the town starts wearing vests as protection.