|First Appearance|| The Venture Bros. |
The Terrible Secret of Turtle Bay
Billy claims to be a boy genius, though in reality he is not a boy, nor has he shown much proof towards the genius claim (though he is occasionally shown repairing or inventing mechanical devices, as well as successfully performing surgery on Dean, after he developed testicular torsion as well as discovering hidden codes like in ORB). He continues calling himself a "boy" genius because "nobody's really impressed with 'Master Billy Quizboy, Adult Genius.'" He took the "quizboy" moniker due to his winning as champion on a game show at a young age. He was later ousted from the show when it was revealed that White, the host of the show at the time, was fixing the game, resulting in Billy being accused of cheating. Billy was inspired to become a scientist and child prodigy by his future friend Dr. Venture during his time as Rusty of the original Team Venture.
He and White are the co-founders, and probably sole employees, of Conjectural Technologies, which they run out of an old trailer which also seems to serve as their home. As seen in "Are You There God? It's Me, Dean", it is unknown what the company actually does, but it appears as if White bosses Billy around, forcing Billy to do housework and company-related tasks while he plays video games (Billy retaliates by passive-aggressively leaving post-it notes reminding Pete of what he should do). However, in that episode, White states that Billy is (more like) a "neurogeneticist," so he may not be as incompetent as most of his colleagues. He operated on Dean to help his testicular torsion and fitted Jonas Venture Junior with a bionic arm similar to his own in the season two premiere, "Powerless in the Face of Death". He also reattached Dr. Venture's arm at the end of "Victor. Echo. November." despite it being detached for some time; in "The Revenge Society" Billy attached Councilman 8's head onto Councilman 3's body creating a 2 headed man. At the very least, Billy is an exceptionally skilled surgeon.
Billy first appeared in "The Terrible Secret of Turtle Bay", where he mocked Dr. Venture for his Ooo-Ray but did not do much else — his appearance here was even more abbreviated than it usually is. He then appeared as an invitee to Prof. Impossible's government think-tank in the episode "Ice Station – Impossible!", awed at the fact that Impossible invited him. He helped Dr. Venture, Sally Impossible, and White develop an antidote for the Goliath serum that Hank had consumed (although Prof. Impossible later claimed the serum was never tested on a human, it was supposed to be used on a "dog or something"). He also featured prominently at Dr. Venture's tag-sale — he and White gossiped about some of the other people attending, whom they later attempted to woo into becoming their arch-enemies. Billy and Dr. Venture also fought over a shrink ray, and Billy criticized Venture for a redundant decal on the ray. In "Escape to the House of Mummies Part II", the shrink ray caused some problems for Billy when he, White, and Dr. Venture attempted to repair it. White and Venture forced Billy to be their human guinea pig, and instead of fully shrinking him, it seemed to do one body part at a time (at first his lungs, then his head). He eventually forced them to reverse the ray to make him normal again, but it merely made a giant out of him without making his clothing bigger. Billy has shown a fondness for the high five.
In "Escape to the House of Mummies Part II", Billy admits that he is a virgin, & at the end of the Season 4 episode "The Revenge Society" it is suggested that he inadvertently loses it to Sgt. Hatred, yet in The Silent Partners Hatred reveals he merely cuddled with him; he loses his virginity in the same episode to three prostitutes whom he believed to be vampires. Billy lost his hand and his eye in an underground Mexican bulldog fighting arena, which White mistook for an underground Quizboy contest. Then his second, "false" eye was sucked out of the socket while he "assisted" Dr. Fantomas with an experiment. (The same experiment that changed Dr. Fantomas' body, and led him to eventually become the villain Phantom Limb.)
In season 4's "Handsome Ransom", Billy and Pete White try to aid Dr Venture in rescuing Hank from the Monarch (none of the three knowing he had already been rescued by Captain Sunshine). During these events, Billy reveals that he is 37 years old after Sgt. Hatred mistakes him for a little kid. Later, in "The Revenge Society," he is kidnapped by his former teacher - now insane and calling himself "Revenge" - and forced to participate in the activities of Revenge's "team." He is left out cold in Dr. Venture's study and eventually found by Sgt. Hatred, as described above. Also in "The Better Man", he becomes a member of The Order of the Triad, but this was because they didn't want to pay his steep medical fee.
Billy has claimed his large head is the result of hydrocephalus, and that his mother referred to him as her "little water baby," and that this condition may be the source of his high intellect (in reality, the condition tends to have more negative effects on intelligence). In some early episodes, his head makes a sloshing sound when he moves it. He also possesses a growth hormone deficiency, the source of his small stature. In addition, Billy has a distinctive speech impediment, giving him an odd lisp and reinforcing the perception that he is a child.
Before the origins of Billy's eyepatch and bionic arm were revealed in the episode "The Invisible Hand of Fate", he once claimed the arm was a weapon, which no one believed. In the episode "Victor. Echo. November.", #21 and #24, The Monarch, and Hank and Dean gossip about the origins of Phantom Limb, all of which tangentially involve Billy losing his eye and/or hand. Though each of the stories is portrayed as being false, it is implied that at least some of the information in Monarch and #21's stories is true:
- The Monarch's Story: When Billy was twelve, he invented a machine which accelerates muscle growth and tried it out on his roommate at the time, Phantom Limb. The machine malfunctioned, driving Phantom Limb insane as well as rendering his limbs invisible and giving him the power to kill by touch. In the aftermath, Limb apparently mutilated Billy out of revenge. The story is notable in that it implies Billy may well have been a boy genius in his childhood, though the Monarch could be referring to Billy being twelve facetiously. The muscle enhancer is later seen being used by Phantom Limb to accelerate the healing of Brock Samson's gunshot wound, which also supports the Monarch's account.
- 21's Story: Billy and Limb won money on Card Sharks which they used to invent a time machine, which transported Limb's limbs and Billy's hand into the future. The results of the story, however, while humorous, (Phantom Limb's limbs and Billy's hand traveling to the future) are also false based on the fact that Phantom Limb's limbs are simply invisible, not absent.
- Hank's Story: Phantom Limb was a renowned stage magician who accidentally transported his own limbs to the moon in a botched trick. In a fit of rage, he then sliced off Billy's arm and ate it. There is no veracity to the first part of the story, as Phantom Limb's limbs are invisible, not absent, though the part about Limb slicing off Billy's hand does apparently mirror the end of The Monarch's version, in which Phantom Limb harms Billy off-screen, perhaps depriving him of his appendage.
At the end of the same episode, when Dr. Venture asks Billy himself how he got his robotic arm, Billy flatly responds: "That's an excellent question. I have no idea." The behind-the-scenes reason for the eyepatch, according to the commentary on "Tag Sale, You're It!" was that Billy's character was originally designed to possess a vast number of unusual affectations, including not only a robotic limb, eyepatch, hydrocephalic head and lisp, but also "to always be in mourning for something," to wear a black armband, etc.
In the episode "The Invisible Hand of Fate", it is finally revealed that Billy lost his hand and eye in a dog fight and had them replaced by OSI: an artificial eye to collect data, and an artificial arm to store it; the OSI's plan was to have him spy on a college professor named Fantomos who they suspected was tied to the Guild Of Calamitous Intent. Fantomos was (as the Monarch said) building a muscle-growth accelerator, and used Billy as a lab assistant. When the machine malfunctioned, Billy's artificial eye was sucked from its socket and lodged in the machinery, causing an explosion. This incident is the reason why Billy wears an eyepatch, and the reason for Phantom Limb's powers. It also contributed to the rise of the Guild, as the OSI operatives involved were reassigned as punishment for botching the mission. Billy later forgot all of this due to an experimental "brain wipe." The creators of the Venture Bros. planned to air this character information near the end of the second season, but its broadcast was delayed due to a decision to expand the season finale into a two-part cliffhanger.