Kirby O'Neil is a character in TMNT and is the father of April O' Neil. He is a scientist and was kidnapped by Kraang in the premiere episode, Rise Of The Turtles. He was transformed into a mutant bat in The Mutation Situation. He then turned human again in The Lonely Mutation of Baxter Stockman. In The Invasion, Kirby turned into a Kraang Zombie. In Battle for New York, he was turned human again by Retromutagen.
Mutant father, Twice reversed.
"I was a man of science until the Turtles accidentally unleashed the beast—I mean, bat—in me. Feral as my new mutation makes me, I still know who my daughter is, and I'll do everything in my power to protect her. "
Kirby is April's father and husband of Mrs. O'Neil. Kirby was kidnapped by the Kraang to help them perfect the mutagen, but Donetello broke him out. He was soon mutated into Kirby Bat when the Turtles dropped all the mutagen canisters out of the Kraang Stealth Ship. He had the ability to fly but lost his mind because of the mutation. Donnie cured him with retro mutagen and was turned back to normal, but when the invasion occurred, he was sadly mutated again into a Human/Kraang Zombie by Kraang Prime. He's very protective of April, a little too nervous, but has a strong sense of will.
History as Kirby
Rise of the Turtles: Kirby is seen walking with his daughter April. The turtles see them attacked by the Kraang and try to save them. Kirby and April are taken away. The turtles manage to find them again and try to rescue them. The Kraang try to take Kirby and April away on a helicopter but Donnie is able to get April off of it. April makes friends with the turtles and vows to get her father back.
The Gauntlet: Kirby reappears in this episode. He sends April a message via Pete the mutant pigeon warning her that something terrible is about to happen and to get out of the city. She and the turtles raid the Kraang compound where he is being held. Leo and Raph find him and ask him about the Kraang. He tells them about their plans for the mutagen. They manage to free him but are pinned down by Kraang laser fire. Kirby picks up a fallen laser gun and holds off the Kraang telling the turtles to save his daughter and the city. He is disarmed and recaptured. April cries in Donnie's arms and he promises her they will get him back.
TCRI: Kirby is not seen in this episode but he is mentioned when April and the turtles discuss why the Kraang wanted him in the first place. He is a psychologist, and of no real use to their goals. They later discover that it is not Kirby the Kraang really want, It is April.
Operation:Break Out: Kirby sends a message through a complex computer data algorithm. Donnie decrypts it and goes alone to save him. He does successfully save Kirby and is reunited with his daughter. When Kirby hugs April however, he looks up evilly. This means that while he was captive, they put a chip on the back of his neck. It is seen only one time in this episode.
Showdown: He was shown in this episode brain washed by The Foot Clan. He tried to attack Mikey but they snapped him out of it. He is now living with the Turtles.
The Lonely Mutation of Baxter Stockman: Kirby is turned back into a human using Retromutagen.
The Wrath of Tiger Claw: Kirby appeared briefly trying to contact April. She would not pick up.
Casey Jones VS. The Underworld He is briefly seen with April giving food out to the Citizens to help out after the massive Kraang invasion
The Deadly Venom He is seen viewing April from his window as April and Casey return from the Theaters. He later appears again in the living room reading when he hears April scream about the snakes and finds his daughter in the ground as a snake slithers away and then comes to the turtles and helps Splinter revive her
History as Kirby Bat
The Mutation Situation: In this episode, Kirby is extremely paranoid of the Kraang returning and has had recurring nightmares. When the turtles accidentally jettison the cargo of mutagen canisters and one falls towards April, he dives to push her out of the way and is coated in the ooze himself. The ooze causes him to fall over the edge of the building and disturb a swarm of bats. His contact with the ooze and the bats cause him to mutate into a bat creature. Mikey tires to call him Kirby Bat, but is scold for his insensitivity. After April blamed the Turtles for her father's mutation, Kirby Bat was last seen breaking out of a cage and flying away.
Fungus Humungous (Episode): Kirby Bat appears as April's worst fear, bats.
Metalhead Rewired: Kirby Bat is one of the many mutants captured by The Kraang. The Turtles broke him out of the mutant prisons along with the other mutants.
Wormquake!: He made a cameo on a magazine April was reading.
The Invasion: When Kirby got struck by perfected Mutagen he turned into a Kraang Mutant.
Return to New York: Kirby Appears only for a short time in the Ending.
As Kirby - Kirby is an average-looking middle aged man with red hair and goatee. He is a professional scientist and psychologist and is on par with Donnie in intelligence.
As Kirby Bat- Kirby Bat is a hybrid human/bat creature with wings,an over-sized head,fangs,and deformed mutagen filled veins. He retains his red hair and beard and also seems to recall his paternal feelings for April, keeping her on a building ledge and bringing her "food".
- Mr. O' Neil's first name is a reference to the legendary comic book creator and artist Jack "The King" Kirby, the idol and role model of TMNT creators Kevin Eastman and Peter Laird.
- The nickname 'Wing Nut' given by Mikey is a reference to the character Wingnut, who appeared in the 1987 cartoon and in the Archie comics. An iteration of Wingnut appears Bat in the Belfry .