He appears as a playable character to take down the gelatin boss down twice and is added to your playable list to use for the rest of the game. He has a Ninja T costume in the shop for players to buy with tickets they get from Perry-ball or the claw game. His favorite weapon is the Ninja Glove and his ability is a reflective shell. He also helps the Phineases and Ferbs, as well as Perry (of the 1st Dimension) take the 1st Dimension Heinz down in his giant robot.
Role in the movie and Show
Terry has a small cameo as he helps to try to take down the Normbots with other agents, but the Normbots were too strong. With the help of Phineas and Ferb's Big ideas though, he, Perry, Pinky, Peter, Albert, Candace, Irving, Stacy, and Isabella. they take down the Norm Bots. He makes a Cameo in episode a Backyard Hong Pong Signing with other animal agents. He makes another appearance in Phineas and Ferb Save Summer at the OWCA graduation ceremony and being captured by LOVEMUFFIN but was freed by Monogram and started fighting L.O.V.E.M.U.F.F.I.N.
In the video game and the movie, he has a dark fedora like Perry but in the official artwork, he has a light brown fedora like Peter.
Agent T was created exclusively for the movie's video game, but since Dan & Swampy liked him so much, they gave him a cameo in the movie itself.
He also appeared in "Agent P Strikes Back", but with a skin error making him green instead of orange, unless it was another turtle.
Terry is from the gelatin dimension. In that dimension, Phineas and Ferb brought Baljeet with them, and Baljeet got a turtle.
Agent T promised to help fight Dr. Doofenshmirtz if the gelatin was drained from his dimension (this is how he appeared in the movie).
When the Phineas and Ferb of Terry's dimension went to the adoption center and chose Perry, they took Baljeet along with them and he chose Terry. Phineas even mentions that he remembers seeing a turtle at the adoption center when they picked out Perry, which must have been the Terry of the First Dimension.
When Perry gives Phineas the pamphlet it has a picture of Terry (or some other turtle who looks like Terry) on it.
Just like Agent P, his color is unlike the real animal.