The character made her only appearance in Showdown At Teeter-Totter Gulch. At first she pushed a character named Belinda and then later blew a bubblegum bubble in her hair after she tries to help Chuckie after being branded by her chocolate bar and knocked down. Tommy was unable to help Belinda because the Junk Food Kid put a popsicle down his diaper. Because she put gum in Belinda's hair, her mother was forced to cut off her hair. The Junk Food's reign is over when Tommy defeats her in a bubble-gum duel, which he won by popping her bubble-gum with her own candy cane (which Chuckie threw to him). As the Junk Food Kid stood with her bubble-gum all over her, she cries loudly. As she does, her mother rushes to her shouting, "Oh I could just kick myself for letting you have that gum, Prudence!", thus revealing her real name to Tommy, surprising him.
After that event, Prudence's mother is forced to cut her hair off, like Belinda's, and then vows to put her off junk food. She later appears on the playground, shown to be eating carrot sticks. Belinda, decides to forgive Prudence, and asks her to play with her, Tommy, and Chuckie. To which she agrees, the other kids realize she's not a threat anymore and play in peace. It's possible that she and Belinda were acquainted once, when Belinda refused to tell Chuckie and Tommy who pushed her and when she asked her in a calm voice to play with them.