Newtralizer

The Newtralizer is a character that debuted in the 2012 TV series. He is an enemy of both the Turtles and the Kraang. He is an amalgam of characteristics of a rejected toy design for Playmates Toys by Ryan Brown and a character created by executive producer Ciro Nieli whilst in elementary school. Due to The Newtralizer's costume, he is likely a parody of Marvel's The Punisher with inspiration provided in part by Judge Dredd. The most obvious feature in this respect is the skull-like pattern on the Newtralizer's chest that resembles the emblem on the chest of the Punisher's costume.

History
The Newtralizer is a resident of Dimension X. He was captured by the Kraang after considerable effort and imprisoned in a secret prison facility on earth because he had a tendency to devour every living thing he met - including the Kraang. In an attempt by Donatello, to free Kirby O'Neil, Newtralizer was also accidentally freed and he promptly goes on a rampage. The turtles ultimately manage to defeat him, but he survives and escapes from the lab and continued his hunt to rid this plant of the Kraang.

He was later detained in the Kraang prison. After Metalhead frees all of the mutants, he escapes from Kraang captivity once again.

Eventually Newtralizer raided a Kraang facility and ​​on this occasion made an acquaintance of the mutant Slash. After they had joined forces Newtrailizer talked to his new partner in the human's language and Slash accompanied him on his hunt for the aliens. However, Newtralizer's thuggery, regardless of the consequences against the innocent people in the area, led to this team to very quickly fall apart.