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Animaniacs Wiki

"And you, Eggie, you love the world too much to ever really care about me."
— Billie

Billie is a gene-spliced lab mouse from Acme Labs who appeared in the original Animaniacs and Pinky and the Brain. Though an experiment gave her super intelligence, she is very oblivious and "ditzy," more similar to Pinky than the Brain in those terms.

She is voiced by Tress MacNeille.


Billie is a tall, skinny, anthropomorphic mouse; in the original series, she has white fur, while in the Animaniacs comics she is gray. She has large ears, a red nose, and pink skin on her muzzle, stomach and curled-up tail. She has blue eyes, purple eyelids, and extra fur atop her head that flaps over like hair. She also has pink pads on beneath her paws. Pinky also says that her head looks like a "very clean carrot," and that she has "more curves than Mulholland Drive."

She very specifically looks similar to Pinky, though even in the animated series her fur is a little darker.


Billie is very airheaded and ditzy in a similar way to Pinky. Though she has more focus than he does, they have a similar sense of humor, way of speaking, and enjoyment of "childish" activities. However, she does not hold the same love for being hurt and ordered around that he does.[1] She and Pinky seem to have the similar trait of falling in love quickly, as in "Brain Noir" she was stated to have dated both Brain and Snowball before crushing on Pinky. (Though, in her previous appearance, she had shown no interest in Brain.[2]) At the same time, she can be oblivious to the intentions and feelings of others, such as not understanding Brain's affection for her while also not realizing that Pinky doesn't hold the same romantic feelings that she does. In the same episode, she is shown to be ruthless and cunning when she needs be.

At the end of "The World Can Wait," an Acme Labs experiment gives her a hyperintelligence, and though she remains very bubbleheaded in personality, she is stated to be even smarter than Brain in terms of intellect, swiftly solving a mathematical problem he had been pondering for months. Brain believes that she might be able to take over the world before them if she wanted to.

Billie seems to pay a bit of attention to her appearance, sometimes seen filing her nails[2] and portrayed as vain in an alternate reality.[3]



Billie appears solely in the Pinky and the Brain segment "The World Can Wait."

She was a lab mouse at Acme Labs of rather simple intelligence. ("You mean she's stupid?" "A bit.") She met the Brain in a maze experiment, referring to him as "Egghead." While he felt an attraction to her, she found him a bit boring and confusing. Brain attempted to woo her that night at her cage, though she was once again confused by his actions and instead preferred his cagemate, Pinky, due to their similar personalities and thought processes. Pinky wasn't interested in her due to his relationship with Phar Fignewton; he did, however, manage to coach Brain in how to better talk to her. Though Brain was horrified by the more idiotic things they'd say, he followed Pinky's advice, telling Billie to call him "Eggy" and complimenting her toenails and carrot-shaped head.

Billie decided that she did like Brain after all, but before they could spend more time together, two scientists entered the lab to put Billie through an experiment. A terrified Billie was then taken to an invention and electrocuted; whatever the test did greatly heightened her intelligence, though her personality remained intact. Her IQ then rivalled even Brain's, to which Brain told Pinky they must rush to take over the world, to prevent her from doing so first.

Pinky and the Brain[]

Billie appeared in two episodes of the Pinky and the Brain spin-off.

She first appears in "Brain Noir," which takes place during the year 1946 and parodies the film noir genre; Billie is a spoof on the femme fatale trope. In her past, she had previously dated the Brain, but after growing tired of his world domination plans, she left him for the hamster Snowball. Pinky says that she "ripped out [Brain]'s fragile heart, then smashed it into millions of tiny little pieces[...] and then squished them all up and ground them into patty." She grew disillusioned with him as well after he "couldn't accept her for what she was," such as making her take breath control lessons to change her voice. Billie then decided to attempt to woo Pinky again by hijacking Brain and Snowball's recent plan for world domination.

Billie went to Brain, claiming she needed help, before fleeing in tears after he focused his energies on conquering the planet. She was then "kidnapped" by Snowball's men. As Snowball then stole Brain's plan for the Fedor-a-matic, Billie prevented Pinky from being trapped by the prototype and slipped Snowball's to-do list into his hat as a clue.

At the completed Fedor-a-matic, Billie operated the machine until being discovered by Brain and Pinky. She then had a henchman take him, before turning on Snowball and having the second goon grab him as well, revealing she had only used him to get the water rights she needed. She then revealed that she built the fedor-a-matic into a large water park in order to impress Pinky, her "one true love." Pinky, completely oblivious to her affections, was excited at the park at first, but became confused and upset when Billie tells him that his days of "being bopped on the head and kowtowing to Brain's every whim" are over. She then kissed him, to which he reacted with panic, telling her that he'll have to go ask Brain's permission before going farther, then screaming and running off into the waterslide. Billie then sighs and says that he's "some kind of a mouse."

In "You'll Never Eat Food Pellets In This Town Again," in which the Pinky and the Brain segments are staged television episodes, Billie is a mouse named Sheila who married the Brain's actor for his fame. She was very focused on her appearance and angry at Brain for not getting her into the show more and for making her "that annoying character" Billie. They lived in a house with Pinky, his sockpuppet girlfriend Margaret, and nearby TV's Dick Clark. When he tried to leave Hollywood behind, she kicked him out of the house. This episode is later revealed to be Brain's nightmare scenario (parodying the real Warner Bros. executives attempting to change aspects of the show).


The Animaniacs comics should be noted as only debatably canon.

In "Acme Valley PTA," Billie is brought in by Brain to pretend to be his wife so that he can gain control of the school PTA. This is complicated when she falls in love with their son, Romy.

An alternate Billie also appears in the twenty-fifth issue of the Pinky and the Brain comics, "The Dark Pinky Returns;" driven mad by seeing The Postman, the Billie of the superhero dimension became Poison Billie and turned to a life of crime. The horrible film also gave her the ability to deliver a poison kiss, in which the recipient of the kiss would be overcome with the desire to see horrible movies. She eventually teamed up with Dark Pinky, only to be defeated by Brain and Pinky, the Constant Wonder.


Comic Stories[]

Pinky and the Brain

  • Acme Valley PTA
  • The Dark Pinky Returns
  • Narftasia (mentioned)


  • "Oh, yeah, I remember you. Egghead."
  • "That's funny, Eggy. You sure know how to talk to a girl! A clean carrot, yeah!"
  • "Oh, Eggy. I thought the electro-polarity had altered the reticular formation in my medulla oblongata."
  • "And you, Eggie, you love the world too much to ever really care about me."
  • "Well, what do ya think? You wanna take over my world, big boy?"


  • Billie was designed to look and act very similar to Pinky; this has been used for speculation that Brain may have hidden romantic feelings for his cagemate.
  • Her role as Brain's ex-love interest with an intelligence to rival his and the threat of taking over the world before him seems to have been taken over by Julia in the Animaniacs reboot.
  • While her intelligence was initially about as high as Pinky's, her vocabulary and intelligence expands greatly after her electrical experiment.