Mutants and Mutagen in Magic: The Gathering® | Teenage Mutant Ninja Turtles

Welcome back, shellheads! Let's dive deep into Magic: The Gathering® | Teenage Mutant Ninja Turtles (and the sewers) for another color pair and examine what gems we fished out from among the discarded refuse of mechanics!

Why Green and Blue for Mutants and Mutagen?

We knew we wanted a color pair to be all about Mutants in some way. We covered the "Ninja" in Teenage Mutant Ninja Turtles last time, and we absolutely wanted to dive into all the weird mutants and mutations that make the TMNT universe unique. Mutants are generally green and blue in wider Magic, and we wanted to lean into Magic's existing expression of concepts wherever we could. The Turtles' many mutant allies include frog, lizards, crabs, and fish, and those creatures tend to be green and blue in Magic.

Did we start out by briefly discussing Magic's mutate mechanic? Not really! Mutate requires a ton of infrastructure and is one of the most complex mechanics we've ever done, rules-wise. I'm sure we'll see it again somewhere, but despite its name being very good for this set, we knew that sneak was going to eat up a lot of our complexity. We brought it up, but it was more of a "we all agree we're not doing that here, right?" mention than an actual attempt to make it work.

Genghis Frog

Today's deep dive will be on Genghis Frog, the leader of the Punk Frogs!

We started, as we often do, with a fairly generic card in the file until we started getting weird with it.

For the green-blue mutation mechanic, we did like how mutate "combined" creatures, so we first tried a sort of riff on the champion ability. We were trying to capture the flavor of "A human recently had contact with a rhino, so being exposed to mutagen makes them into a rhino-human hybrid." We also called this mechanic "mutagen" in testing. I'll call it "old mutagen" here to be slightly less confusing.

We also had a lot more typal rewards in the set that cared about having multiple creature types to make the creature type part matter. This mechanic was often strong, but it was awkward to play with as you had to (temporarily) lose a creature to use it effectively. When you could use it with creatures that had been locked down by enchantments or had good enters effects, it was too strong.

The mechanic was "polar," meaning it was either very bad or very good with little in the middle, and polar mechanics often have difficulties later in the process once Play Design gets involved. At a certain point we realized it also was playing in similar space as the behold rares from Lorwyn Eclipsed. We went into the Magic: The Gathering | Teenage Mutant Ninja Turtles Vision Summit (the first chance the rest of the studio has to see our work on the set) with an updated card that used "old mutagen." (Man, mutagen can be bad enough, but all old and congealed? Maybe I should have chosen a different word to differentiate them …)

Coming out of the Vision Summit, "old mutagen" was the most discussed mechanic. Here are a few things we discussed:

• While we had more typal effects in the set at the time than we do now, adding creature types was very unimpactful and not really worth the words. It helped sell the flavor, but that was about it.
• The original creature returning after the creature with "old mutagen" left didn't really make sense with the flavor at all, but without it the mechanic was more like emerge, which wasn't exactly what we envisioned. Creatures weren't dying here, and emerge is a tricky mechanic to get right. The flavor wasn't really lining up.
• The card advantage from getting the creature back was going to make it hard to balance correctly. That part was quite strong.
• Most importantly, though, the text is pretty different; it played too similarly to sneak. It had one of your creatures replace another, and you could reuse the first creature and its enters effects later. We wanted the focus to be on sneak. This mechanic might need us to change the set (like weakening enters effects) to work, and that would make sneak less appealing.

So, we immediately tossed "old mutagen" into Dimension X and started looking for another green-blue mechanic. Something we had been discussing since the start of design was what noncreature token the set wanted to use. Obviously, we wanted some Food tokens, as pizza and junk food are featured prominently in TMNT lore. Going too deep on Food, though, can really slow down a format by injecting too much life gain. We knew we had room for another one if we wanted, but Treasure was not a good fit for the TMNT universe. The thing they treasure most is a hot, fresh, and weird pizza, and we already had that covered.

It was Erik Lauer (our Splinter) who first suggested that if the mutagen mainly increases the size and power of the things it mutates, we could use a simple token that gives a +1/+1 counter to represent something being exposed to mutagen. I believe he pitched it as "like a Map token, but less fiddly."

We started playing with Mutagen tokens, and they played well. It also let us feature the iconic cylinder filled with bubbling green ooze in many more places in the set than just on a single rare card, The Ooze.

Once Play Design got a hold of ol' Genghis, we needed to pull back on the ease of doubling and also wanted to simplify him a bit.

As a four-mana 4/4, this overlapped a little too much with our uncommon version of Michelangelo. We also wanted to increase the strength of green-blue in Draft a bit. Ben Weitz suggested taking Genghis Frog all the way down to two mana so you could get him online before most of your other Mutants. So, it all came together for the final card!

Mutagen Man, Living Ooze

Mutagen Man, after a brief initial stint with the "old mutagen" mechanic that was very awkward and involved counting the number of creature types, went right into the file as this card:

Once we had Mutagen tokens, we knew Mutagen Man had to make a lot of Mutagen tokens. It's literally what he's made of, and an cost design seemed perfect. We talked about what color this fairly novel ability that makes artifact tokens cost less could be, and green worked as one of the colors we could do it in.

Everyone on the design team and Play Design liked this card, but it made slightly too many "rectangles" (which is slang we use for tokens, especially when you enter to create some number). So, we changed it to a 2/2 for . Once Constructed testing started in earnest, Play Design built several green-blue (and sometimes white) decks focused on Mutants and counters, and this card ended up being fun enough that they wanted to push it a little more as a finisher. It went up to a 2/3 and gained trample. This was one of the smoother rares in the set; it only had like five versions!

Venus, Torn Between Worlds

Venus is a character with a crazy history in the TMNT universe. She debuted in the live-action series Ninja Turtles: The Next Mutation as the "fifth Turtle" and the first female Turtle. That TV series was a very loose continuation of the first three TMNT movies, but it only lasted for a single season.

Venus lay dormant for 25 years until the comics brought her back in 2022, and that's the version we stuck closely to. She was one of the Punk Frogs, which were humans mutated into frog-human hybrids by mutagen. But she was captured, experimented on, and given Turtle parts by a mad scientist (Comics!), which accounts for her flavor text and the stitching you can see in her image.

We felt the Fungasaur ability was a cool fit for her rebuilding herself and played into the green-blue counter theme (try it with Novel Nunchaku in the set!). She originally leaned into Mutagen as you can see above, but we actually had too many cards that made Mutagen and not enough payoff cards for having put the counters on your creatures, so we made her a counters payoff. We leaned into her mystical future-seeing powers for a new ability that draws a card. (Did I not mention she also developed mystical powers? Comics!)

This was the effect that green-blue needed in Limited, but the activated ability was awkward in that we needed to give it a high cost so you couldn't double up on card draw by activating it multiple times per turn, but that made it too weak. In the end, Play Design and I wanted it to be a single trigger per creature at a much lower cost. And that's how Venus the card (and the character) was Frankensteined together!

As you can see, the green-blue archetype stayed and was always about mutants, growth, and change, but the way we expressed mutation evolved quite a bit. Join me next time as we look at the more aggressive side of mutants with red-white!

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Magic: The Gathering | Teenage Mutant Ninja Turtles releases on March 6, 2026, and you can preorder cards now from your local game store, TCGplayer, Amazon, and elsewhere Magic is sold.