Dog Pound

Dog Pound is actually the mutated Chris Bradford. He got mutated and turned into a giant dog. He has a normal hand and a another giant hand which attacks with that. He got mutated in Episode 9.

After Mutation
After Dog Pound got mutated, he got a mission from Shredder to throw toxics at the sewer where the turtles live. Since he was too powerful for the turtles, it would be easy to succeed. However, he got beaten. His next mission was to get April's phone so he can locate the turtles' hideout. This time he allied with Baxter Stockman and his mousers so he can succeed, but he lost and the phone broke. After a long time he was trapped with the turtles in Stockman's Maze of Doom. He allied with the turtles to get out of the Maze of Doom.

Second Mutation
"Since he didn't like being mutated, he decided to get his human form back. He captured Stockman and forced him to make him human again. However, his plan didn't go well, as he fell into the ooze and mutated again and became Razhar."