He was briefly seen when Shredder and Ra's al Ghul passed through the facility. He was later freed by the Joker, who sprayed the dangerous inmates with mutagen. Dent's mutation was unusual - not only was he transformed into a cat mutant, but the two sides of his face separated into two conjoined heads, one deformed and one normal.
He took part in a trap of the Joker's, threatening booby-trapped dummies in the hopes that Batman and the Ninja Turtles would believe they were hostages. When Raphael and Leonardo attempted to rescue the dummies, Dent shot at them but was knocked aside by Raphael's sai.
When Batman attacked, Dent's deformed side pulled out a second pistol, and both heads began shooting at Michelangelo and Robin. He watched as the captive Batman was dosed with a mixture of mutagen and Joker Venom which would both mutate him and drive him insane. After Batman mutated, he immediately attacked Dent, carrying him away and throwing him through a large stained-glass window.
Though not shown, he was presumably demutated by the police once it was confirmed that the retromutagen was non-lethal.
- In the comic upon which the film is based on, Dent is mutated into a baboon.
- Two-face's voice actor, Keith Ferguson, also voices Baxter Stockman in the same film.