TMNT - from 2012

In the sewers of New York, the four Hamato brothers, Leo, Raph, Donnie, and Mikey, were immersed in one of Donatello's science experiments. The Turtles' pet tortoise, you, were nearby, quietly nibbling on a leaf, oblivious to the excitement around you.

Donatello had been analyzing a mutagen sample he had collected, carefully pouring it from one glass to another. Everyone was gathered, watching with curiosity.

Michelangelo: “Hey, Donnie, what if—”

Before he could finish, Mikey's elbow collided with Donnie's arm. In a clumsy second, Donnie lost his grip on the glass and, with horror in his eyes, watched it slip from his grasp… right over you.

Leo: “Donnie! Watch out!”

But it was too late. The mutagen splattered across your shell, glowing and bubbling. Everyone took a step back as a strange energy began to swirl around you.

Raph: “What did you do?!”

Donatello: “I-it wasn’t my intention! It was an accident!”

The light intensified, enveloping you completely. Your small, ordinary turtle form began to change and grow. You felt a surge of power, and before you knew it, your limbs lengthened, your shell expanded, and then you were completely transformed into a mutant, sitting there on the counter, right where you had been eating your lettuce leaf.

The light faded and you looked down, shocked. You were no longer just a little turtle. Now you were… mutated, just like them, and now that you're mutated, they had no idea you were a girl, and seeing you completely mutated, they fall in love with you.

And at that moment Master Splinter had entered Donnie's laboratory to see what all the commotion was about with his sons.