When Uroko first steps out of the machine, he is disoriented and doesn't know where he is. Polidorius tells him that he created him and tasks him with bombing the sewers to start the flooding. Uroko calls him crazy at first and refuses, but Polidorius pushes a button on a device which zaps Uroko into near unconsciousness, telling him he'll do worse if he doesn't comply.
Uroko does as instructed, and Polidorius says they make a great team, which the mutant describes really as being more like master and slave. Just as he's finished his work, he hears some noise on the street above and peeks from below a manhole cover to investigate. There, he sees April and Vernon wrapping up a story about a new luxury apartment building. April hears noise coming from the manhole after they've finished, and thinking it's the turtles, she pops down into the sewer to greet them, only to be ambushed and captured by Uroko.
Uroko brings April back to the doctor's lab, and Polidorius tells her that he's going to run experiments on her. The two of them cram her into the Shinka Sokushin Machine, as she drops her Turtlecom. Meanwhile, Uroko returns to the sewers and encounters the Turtles. He asks if they're looking for "the reporter" and they realize he's done something with April. Mikey throws his nunchaku at Uroko, but the fish hits them with an "electric eel ray". After recovering, they all charge at him at once, only to be pelted by a barrage of quills Uroko fires off of his body. Leo tries to block them with his katana, but they overwhelm him and he gets knocked into the water. Uroko then stretches his tail out and grabs Donatello's bō, flinging him hard into a wall. Finally, Raphael tries to put him down by throwing his sai at him, but Uroko catches them and throws them back, pinning Raph to the wall by the arms. With his attackers out of commission, he skulks off to Polidorius' lab.
The turtles end up at Polidorius' lab and meeting the doctor and Uroko there, only to find that he has mutated April into a hangyojin as well. Leo goes to charge the villains in anger, only to be put down by Uroko's electric eel ray again. Don finds their plans and realizes that they're trying to bomb the city. April and the turtles run off to defuse the bombs.
They don't find all of them and end up at the luxury apartments to find Polidorius and Uroko there. Polidorius detonates the rest of the bombs and starts flooding the apartments. Uroko realizes he can just swim away and leaves the doctor yelling for help. Out in the water, Uroko decides how happy his is now and introduces himself to some sea life.
Powers and abilities
- Electric eel ray: Uroko can discharge voltage like an electric eel, stunning his target.
- Quill discharge: Uroko can sprout quills on his body and fire them off in multiple directions at once.
- Elasticity: While not shown to a great degree, he was at least able to stretch his tail to an astounding length.
- Super reflexes: Uroko was swift enough to pluck Raph's sai out of the air.
- Undies: Uroko's only article of clothing is a pair of red briefs.
- Wristwatch communicator: Uroko kept in touch with Polidorius while planting bombs in the sewer with a wristwatch with cam technology.
- Unlike the cartoon character he is based on who is called Ray, this character is only referred to as by his species (hangyojin) or by Polidorius and Michelangelo as "Uroko-chan" - uroko being Japanese for scale (in the context of scales of a fish or serpent), with "-chan" being a Japanese honorific utilized if the subject is younger or smaller than the speaker, or as a term of endearment. The only time the word "ray" is used when Uroko discharges electricity and calls it his "Electric eel ray".
- The fish species he was spliced with are not mentioned, other than calling his electric attack the electric eel ray. He does have pectoral fins under his arms that resemble a ray's "wings" and sprouts quills like a porcupinefish.