Mario and Luigi finally make it back to Brooklyn, but find themselves entangled in a babysitting job forced upon them, with a child, Junior, who seems to be more than they can handle. Even worse, Junior happens to find the warp drain pipe to the Mushroom Kingdom that Mario and Luigi arrived from...
This episode provides examples of the following tropes:
- Babysitter's Nightmare: Junior's parents have a hard time finding a babysitter for him due to his reputation as a troublemaker. The Mario Bros. get roped into babysitting him when they take a wrong turn through a pipe and Junior's parents mistake them for the babysitters.
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Children Voicing Children: Junior's voice is decidedly not an adult-as-a-child-voice, when compared to the Koopa Kids. - Convection, Schmonvection: The Mario brothers are trapped in a room slowly filling with a boiling lava, but suffer no ill effects. In Mario’s case, the lava is even shown to have reached waist height before he gets out.
- Food as Bribe: Unintentionally. When Junior's mother welcomes Mario and Luigi into their home, not knowing that they're not the actual babysitter(s), she offers lasagna in the fridge, the idea of which Mario immediately latches onto. Luigi tries to back out, but Mario silences and admonishes him.
- Heel–Face Turn: Downplayed with Junior; while he isn't evil, he still is very prone to misbehaving and causing problems for others. He even teams up with the Koopalings to play pranks on the Mario Bros., but once he realizes they're not just playing games and the Bros. save him, he becomes a lot nicer.
- Here We Go Again!: At the end of the episode, Junior's parents ask the Mario Bros. if they can babysit Junior again the following Friday. Junior is enthusiastic about this, but the Mario Bros. aren't so much.
- Non-Nude Bathing: When Mario, Luigi, and Junior get back to Junior's house at the end of the episode, they get there as soon as Junior's parents come back. Junior warns them that they won't be able to babysit again if he doesn't get his bath, so they fill the tub and just chuck him in fully clothed.
- Plug the Volcano: Mario and Luigi stop an erupting volcano by launching a boulder into the air while Mario guides it into the mouth of the volcano via his Super Leaf power. Making things slightly more unusual is that this volcano appears to have a pipe as its spout.
- Would Hurt a Child: Kooky, Bully and Cheatsy have no qualms with putting Junior in the Pipe Maze which they plan on filling with lava.
- Wrong Turn at Albuquerque: The Mario Bros. wind up in Junior's house due to taking a wrong turn through a pipe at the Mushroom Kingdom.
- You Have Outlived Your Usefulness: After the bratty Junior helps Bully, Kooky, and Cheatsy trap the Mario Bros. in a cave, the Koopalings repay him by tossing him down a pipe and into a Pipe Maze.Cheatsy: Look, kid. You've been real helpful, but the truth is, Junior, we really don't like you very much.
Bully: Which is why we're getting rid of you.
Kooky: Right now!
