Mutagen Man Unleashed
Teenage Mutant Ninja Turtles (2012 TV Series) episode
Title screen
Season Code: 204
Episode: 30
Guest stars Josh Peck
Original airdate November 9, 2013
Written by Kevin Burke & Chris Wyatt
Supervising Producer Ant Ward
Producers: MacGregor Middleton
Peter Hastings
Ciro Nieli
Directed by Sebastian Montes
Voice Direction Andrea Romano
Supervising Director  Ciro Nieli
Episode chronology
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"Invasion of the Squirrelanoids" "Mikey Gets Shellacne"

Teenage Mutant Ninja Turtles Season 2
October 12, 2013 - September 27, 2014
List of Teenage Mutant Ninja Turtles episodes


  1. The Mutation Situation
  2. Follow The Leader
  3. Invasion of the Squirrelanoids
  4. Mutagen Man Unleashed
  5. Mikey Gets Shellacne
  6. Target: April O'Neil
  7. Slash and Destroy
  8. The Kraang Conspiracy
  9. The Good, The Bad, and Casey Jones
  10. Fungus Humungous
  11. Metalhead Rewired
  12. Of Rats and Men
  13. The Manhattan Project, Part 1
  14. The Manhattan Project, Part 2
  15. Mazes & Mutants
  16. The Lonely Mutation of Baxter Stockman
  17. Newtralized!
  18. The Wrath of Tiger Claw
  19. Pizza Face
  20. The Legend of the Kuro Kabuto
  21. Plan 10
  22. Vengeance is Mine
  23. A Chinatown Ghost Story
  24. Into Dimension X!
  25. The Invasion, Part 1
  26. The Invasion, Part 2

Season 1Season 2 - Season 3Season 4 - Season 5

"Mutagen Man Unleashed" is the fourth episode of the second season of the 2012 TV series, and is the thirtieth episode overall in the series. It first aired on November 9th, 2013.


Donatello obsessively experiments with mutagen in a bid to find a cure for April's mutated father. Unfortunately, this puts April in danger from a new threat; Mutagen Man!


Major Characters

Minor Characters


The episode starts off with Mikey watching another cartoon show called SRMFF that he had found multiple copies of amongst a box of old video tapes in a random dumpster. The other initially complain about how bad the apparent plot synopsis is - and how the words said do not nearly even match the movement of the characters' lips, but all of the brothers then get into it after a short while....

However, Donnie soon leaves after watching a scene in which a male character is rudely turned down by a girl of similar age that he likes, and heads off to his lab. Donnie then talks about April right in front of the mutated Timothy, while trying to create an antidote reverse-engineered from the Mutagen somehow. However, he fails and instead, ends up freezing the beaker with the solution. He then vows to create a cure for Kirby in order to win April back, even if it's the last thing he does. As soon as he leaves, Timothy's tongue then comes out of the container and sucks up the little bit of Kraang Mutagen remaining there....

Meanwhile, at Roosevelt High School, April makes a resolution to start fresh and forget about everything that has happened - The distressing mutation of her father and her meeting the Turtles. However, she then gets knocked down by a hockey puck and comes face to face with Casey Jones. After she gets herself back up, April has an immediate dislike for him, despite the revelation that she has been assigned to him as his tutor (and Jones desperately does not want to loose his rank on the hockey team, which is apparently hanging in the balance). Thus, she agrees to help him in Trigonometry, and so they set up their very first session in the park...

On a rooftop the following night, Mikey comes across a lone Pizza box with only one remaining slice inside. At first, he is realistically suspicious of it, but then decides to go and eat it. However, he then notices three figures snooping about nearby and, before he even knows it, he is tackled by his brothers, who are practicing some stealth and misdirection and inform him what it's all about. While the others are busy, Donnie goes to the park, already knowing that April studies there a lot - and he spots April and Casey swinging and talking simultaneously... He suddenly becomes quite a bit jealous when Casey reaches out to wipe a small smudge off of her face. A partially jealous Donatello then tries to get even closer, but lands in a dumpster, startling the two.

Back at the lair in his lab, he vents his jealousy of April "seeing" Casey (a "punk, human kid"), while also installing a voice box for Timothy...Timothy then tells him that he now likes April too, but Donnie's too upset about what he saw to pay any sort of attention to him. At that moment, Splinter tells Donatello to enter the The Dojo for a brief moment, which allows Timothy to drink the whole canister of Mutagen without even being noticed... Splinter decides to teach Donnie to "enjoy" falling down, which confuses the latter a whole lot. After a few times of doing this, Splinter tells him that the point of this exercise is that no one can possibly be forced to enjoy or like something.... Of course, Donnie realizes that he means that Donnie cannot force April to like him in any way. Unbeknownst to either of them, however, Timothy quickly breaks free in search of April on the surface, as the Mutagen is somehow able to have some affects on the growth/expansion of his entire body. In the city, he tries to get someone to help him find her, but every single person (including the Police, whom confront him) is clearly terrified of him.

The Turtles themselves then head out to search for Timothy, as Donnie tells his brothers everything that has happened, including that he knew about the fact that April and Casey are seemingly "dating". They soon pause and decide on splitting up into two teams, one going to the park and the other heading over to April's apartment. However, both teams miss her, as she is currently one her way home with Casey. At that very moment, Timothy finds April, but Casey tries to fight him off with a lead pipe that he rapidly finds in the trash. Unfortunately, his weapon is melted and he then gets knocked to the ground, and April is forced to take over the fight for a minute. Timothy tries to reason with her, but she continues to attack him, as Casey jumps back in, only to be kicked out yet again... Timothy then tries to grab April as she cowers in fear. Just then, Casey gets onto his bike and rescues April with it - and he speeds out of the alley, with Timothy closing in behind. Casey, however, manages to send him reeling into a truck as they make their escape. Timothy tries to pursue them once more, but two of the Turtles then find and fight him. Before he can kill Raph, Leo then appears, steps in and frees his brother by cutting off one of the Mutants' hands. However, Donnie stops Leo before he can do any more damage - and explains that Timothy only wants to help them out. However, the latter tells them that he wants April to be his friend and that he does not want to help the Turtles whatsoever. Just then, he powers down and the Turtles actually succeed in getting him into The Shellraiser because he has used up all of his Mutagen (which is his one and only source of power).

On the way back to the lair, Raph asks why they are bringing Timothy back. In addition to saying that Timothy wanted a friend because of how he spoke about April, Donnie says that maybe his DNA could help him synthesize an antidote for both him and Kirby. During the conversation, however, he drinks yet another canister of Mutagen and busts out of the Shellraiser. The Turtles then prepare for the possibility of splitting up again, but Donnie tells them that he knows where Timothy is clearly and insistently heading to: April's apartment.

Meanwhile, at the apartment, Casey is carefully scanning the area for any more unsightly Mutants. Before she goes inside, however, Casey talks about when their next meet-up should be. At that moment, Timothy finds the location and prepares to go after April once again, but the Turtles then show up on the spot as well - and Leo tells them to keep him in the alley way to prevent Casey from being able to see them...April notices the fight, however, and she then takes matters into her own hands and manages to keep Casey from walking in the direction that the Turtles currently are (Casey agrees on walking to his house using a different route). She then peers into the alley and quickly deduces that they might've been responsible for the attack on her....The Turtles narrowly fend him off, but Donnie comes up with an advisable plan to use both camouflage and misdirection to distract him. Donnie then goes into the Shellraiser and comes back with a canister filled with some of the freezing solution (which Timothy drinks). The others root for the success, but Donnie sadly looks over the now frozen solid Mutant...

Back at the lair, the Turtles are watching yet another SRMFF episode, while Donnie is sitting secluded on another couch, mourning over the loss of both Timothy and April. Splinter then shows up and tells him that, while April is choosing to stay away from the Turtles, there is a constant supply of hope that both of them will reconcile eventually... Donnie then watches on as the female character on the show from before returns and kisses the nerdy kid (who had found her and saved her life), restoring his optimism.


Raphael: (about Super Robo Mecha Force Five) What is this nonsense? It's terrible!
Michelangelo: Terribly AWESOME! I found these old tapes in a dumpster.
Raphael: Tapes?
Leonardo: Dude, this is AWFUL! And you guys complain about Space Heroes!
Raphael: Their lips don't even match what they're saying! I could NEVER watch a show this bad!
(a couple minutes later, everyone's glued to the screen)

Michelangelo: (after stealth attack from Leo) What was THAT?
Leonardo: THAT, was a stealth attack. And that is what we're gonna be doing in today's training session.
Michelangelo: No fair! I couldn't see you coming!
Raphael: That's why it's called 'stealth', genius.
Donatello: Why would you eat a slice of pizza you found on the roof anyway?
Michelangelo: Roof pizza is like one of my top ten favorite types of pizza.

April: Have you ever actually opened this book?
Casey: Eh, school isn't really my thing, When I graduate, I'm either gonna become a professional hockey player, or an international bounty hunter.
April: Those are quite the options.
Casey: Who wants a normal life anyway, right?

Donatello: Can you believe it? And they were SWINGING together! SWINGING! And then she LOOKED at him! And I mean THAT look! It looked like-like this (doe eyes). Why was she even with him? Because he's human, thats why. BIG DEAL! Do you know how many people are human?

Splinter: Today, I will teach you to like falling down.
Donatello: Why would I — (gets floored)
Splinter: Did you like it?
Donatello: No!
Splinter: Then let's try again. (A couple minutes of Donnie falling down later.) Do you like it yet?.
Donatello: No, Sensei! Not at all!.
Splinter: I see. So you cannot MAKE someone like something.
Donatello: Of course not! Who would want to… Oh. You're talking about me and April...
Splinter: My son, for someone so intelligent, the obvious often alludes you.

Donatello: (about April) She might be at the park! (mutters) On a date...
Raphael: And you know this HOW?
Donatello: I… might've been… following her?
Michelangelo: Well, THATS not creep-tastic.

April: (faced with Mutagen Man) Donnie's monster? Can't I go a WEEK without some mutant attacking me?
Casey: (gets in front of her)
April: What are you doing?
Casey: Whatever that thing is, it's pure evil, and COMPLETELY COOL LOOKING! I'll handle this, sweetheart.


  • This episode marks the first appearance of Casey Jones in the 2012 TV series.
  • Like Space HeroesSRMFF is used to foreshadow events for the episode or series.
  • When Casey is walking April to her apartment, you can see "Second Time Around" appearing in the background, which is April's shop in the TMNT comics, and the 2003 series.
  • The truck driver driving the truck that hit Mutagen Man was Fong from the Purple Dragons.
  • When Raphael says to Donatello "As useless as a trench coat on a turtle" he was referring to the original 1987 series, where the turtles would simply wear a large trench coat and feel free to walk around in daylight perfectly disguised. 
  • The voice box that Donatello gave for mutated Timothy, it has a sign "Laird", which is the last name of Teenage Mutant Ninja Turtles co-creator, Peter Laird.



Mutagen Man Unleashed/Transcript



TMNT - Casey Jones Makes His Debut