Acting as a continuation of the last episode, Peach is screaming in pain when Shrek comes to examine the scene. He looks for her newborn baby but instead finds an evil turtle, named Bowser Junior, who frantically begins to attack him violently. He begins breathing fire and starts attacking Mario once he knocks Shrek down. Mario tried punching him and knocks him onto Peach. Bowser Junior stands up, grabs Peach, and runs out of the hospital room. Mario manages to put out the fire and finds that Shrek is unable to help him save Peach. Luigi instead has to join him.
In the kitchen, Black Yoshi is busy pouring some "real, black man" Grape Kool-Aid for Mario with Mr. Pig. Before Black Yoshi can take the glass of Kool-Aid for Mario, Junior runs in and Peach cries out for help. Mario then heads in and orders Black Yoshi to kill the turtle. He is able to ward off Junior and receives a huge thank-you kiss from Peach, but claiming to Mario that he is stealing Mario's girlfriend, so Mario tries to win her back over. Unfortunately, she protests and the episode ends with Bowser tackling Mario.
- This episode marks the very first appearance of Bowser Junior.
- This is the shortest episode of the entire Mario & Luigi's Stupid and Dumb Adventures series.
- Luigi and Mr. Pig strangely disappeared in this episode after their short appearances.
- The episode's title appears to be a parody of the "Teenage Mutant Ninja Turtles".
- Luigi disappears after Bowser Jr. was wounded by Black Yoshi.