The Grim Adventures of Billy and Mandy Wiki


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Alias William, Captain Spring Green
Nickname "Billy"
Classification Human
Gender Male
Age 7-8
Residence Endsville
Relatives Gladys (mother)
Harold (father)
Sis (aunt)
Nergal (uncle)
Nergal Jr. (cousin)
Pets Milkshakes
Mr. Snuggles
Affiliation Underfist
Occupation Student at Endsville Elementary School
King of Asgard
Real world information
Appears in Grim & Evil
The Grim Adventures of Billy & Mandy
Underfist: Halloween Bash
First appearance “ Billy & Mandy in Trepantation of the Skull and You” (Pilot)

"Meet the Reaper" (Official)

Voice actor Adam M. Burton (Billy and Mandy in: Trepanation of the Skull and You) (1995)
Richard Steven Horvitz (1999 - present)
Billy is an idiot, and will only understand the most extreme of punishments.

William "Billy" is one of the main characters, and is Mandy and Grim's friend. He is a dim-witted, happy-go-lucky boy living in Endsville. He has an extremely low IQ of -5, having been outperformed by a shovel and 2 candy bracelets on an IQ test. Good-natured and incredibly dopey, Billy's curiosity tends to get him into trouble he can't get out of by himself. Billy enjoys the company of Mandy and Grim and would do just about anything for them.


Billy and Mandy's first meeting

Billy and Mandy's first meeting.

Billy and Mandy met as babies when he came over to her house, repeatedly ringing her doorbell to annoy her enough to answer. When she did, the first thing she said to him was, "Are you some kinda idiot?". When he pointed out that she had no nose, he proceeded to shove an ice cream cone into her face, apparently creating a makeshift nose for her. Angered, Mandy punched Billy in the face, calling him a creep, and slammed the door in his face. Billy simply laughed and said, "She digs me". According to Harold, that day was the start of Billy and Mandy's friendship.[1]

Years later, while Billy and Mandy were celebrating the tenth birthday of his pet hamster, Mr. Snuggles, the Grim Reaper appeared to claim the old hamster's soul. However, Mandy refused to give the Reaper the hamster and offered to play a game for its soul instead. If the Reaper wins, he would get the hamster's soul. Grim, assured of his victory, sweetened the deal on their behalf by promising that if they win, he would be their best friend "forever and ever." Grim took Billy and Mandy to play, where they competed in Grim's favorite game—limbo. Mandy cheated, and Grim was doomed to be the "best friend" of the two kids for all eternity.[2]


Due to Billy's idiotic, foolish desires, which he orders Grim to bring about, he is often the cause of Grim and Mandy's mishaps. Billy, despite being a complete moron, sometimes has random bursts of cleverness and cunning, especially when he wishes to attain his said foolish desires. Although good-natured and happy-go-lucky, he has occasional fits of stubbornness, violence, anger, and rage, which shows insanity that even Mandy seems to fear. While Billy is the most innocent character of the three, he ends up causing the most problems due to his irrational and often impulsive choice of actions, usually by deliberately doing what the others expressly told him not to do. Billy is terrified of clowns to the point of having recurring nightmares about them, although eventually, due to an encounter with his inner frat boy, his fear is transformed into a psychotic loathing and hatred for them, as shown in Attack of the Clowns. He is also scared of the mailman and spiders, which is quite unfortunate because he is Jeff's father (Billy hatched his egg), and Jeff is a huge spider.

His stupidity has seemingly given him the power to be extremely oblivious to pain as in many episodes he is shown to be having his own flesh rip apart like his nose exploding or bones jutting out from his body. He can be seen immortal in this sense as he has always been able to get out of seemingly lethal encounters, with or without Grim or Mandy like his encounter with the Kraken.

He is also shown to hate rules which an entire episode is dedicated to this hate in which he learned his lesson when he got eaten by an alligator and broke his dad's motorcycle.

Billy has clearly inherited his stupidity and gross behavior from his dad since they both have acted very similar to each other; not to mention Mandy occasionally bashing him on the head with a hard object must cause a little brain damage aswell,so Billy being a moronic idiot is really entirely not his fault at all.

Billy has displayed some sexism towards Mandy when he was reluctant to let her play a board game with him and Irwin in the episode "Who Killed Who?"; and then refused to let her join his baseball team in the episode "Bad News Ghouls", just because of her being the opposite gender of him. Even though Mandy was a much better baseball player than Billy was and an asset for the team; he still did not want her to join the team and even got the other players to harshly chant "No girls on our team!", forcing Mandy to sort of dress up as a boy named "Manfred" just to play the game which Billy was totally oblivious to and completely fell for. Even though it is rare and of character for him Billy has clearly shown that he can be just as angry and violent as Mandy can; when both the episodes of "My Peeps" and "Attack of the Clowns" he had basically become a psychotic maniac and tried to viscously attack his friends with Grim's scythe that he had gotten a hold of, forcing the others to run away for safety from him as he chased them around trying to cut and slash them. Also whenever his so-called "son" 'Jeff the Spider' makes an appearance in the show to visit with his beloved "dad"; Billy either freaks out and runs away and hides in fear from him, of gets very mad and intentionally inflicts pain on Jeff by using large and heavy items of furniture to show his aversion and disgust towards the big nice Spider.  

Physical Appearance

Billy has a big pink nose and beady little black eyes all inherited from his father Harold; and red hair that he inherited from his mother Gladys, plus his skin tone is more on the reddish side. He wears a white short sleeved t-shirt with a thin horizontal blue stripe; plus a pair of blue jeans, finally a red baseball hat on his head plus a pair of white and red sneakers on his feet.

He becomes a scientist for Underfist later on. By then, he starts wearing safety goggles, a white lab coat, purple gloves, and black boots.[3]

Powers and Abilities

  • Heightened pain tolerance: In many episodes and because of the fact that he is in an animated cartoon, he is shown to have his flesh ripped, body parts cut off, burned, eaten, and many other seemingly lethal encounters but always ends up surviving what would normally kill off other characters. This may be due to his stupidity to be so heightened that he is oblivious to pain and danger that he is indifferent to it as he is to life itself.
  • Heightened Confidence: He is shown to have no shame or fear in certain times of danger which can prove useful to him being oblivious to the danger which goes with his pain tolerance that makes him the stunt monkey and meat shield of the trio.
  • Nose Mucus Adhesive: Billy can make use of his nose mucus to make things stick together like when he used his snot to fix the dismembered boat in the movie.
  • Master Distraction Artist: He is shown to be effective in distracting and buying time for people like in the Halloween movie where he is able to distract Jack by mooning him long enough for Mandy to set up an abundance of prank traps.
  • Taunting: Going with his distracting capabilities, he is has the ability to be so annoying and taunting that he can send anyone into a fury to go after him like in the anger mismanagement episode.
  • Nose Balloon Lift: It is shown that his noes can be used as an inflatable hot air balloon and can be held on by the nose hair to fly.
  • Befriender: Billy has the ability to be attached and befriend to unlikely beings to have mutual likings with each other. Whether it be inanimate objects like rocks, to underworld mutants like the kraken or the chacabra, or even Sperg temporarily in some episodes. This is limited to unfortunately to anything he does not fear which includes spiders, the mailman, and clowns in which he will act hostile or scared to.
  • Unlikely Translator: Billy at times is shown to speak of things only he can say like when he did a special call to signal the kraken to help them win a race. He could also understand and cunningly make Fred Fredburger's seemingly meaningless phrase about eating nachos into a moral of the story about their capabilities in the movie.
  • Super Yogurt Hero: He has the ability to turn into a muscular green superhero that can fly, have super strength, and shoot strawberry yogurt from his armpits.
  • Werewolf: Although temporary, Billy turned into a werewolf by the zombie martians in one episode.
  • Uniquely Stupid Brain/ Living without a brain: Billy's brain is so uniquely stupid that it had the power to destroy a brain washing machine the martians had. However, he may not even have a brain also stated in some episodes which shows he is able to function (although extremely low intelligence) normally without one.

Relationships with other Characters

The Grim Reaper

After having lost a game of limbo to Billy and Mandy, Grim was forced to become the two's best friend forever. If Grim doesn't honor his commitment to be Billy and Mandy's best friend forever he'll go to underworld jail. Billy is seemingly aware that Grim doesn't like him, most likely because he tells Billy that at every opportunity. However, he still treats Grim like a valuable and loyal good friend, even though he never listens to him. Nevertheless, Grim has shown that he seems to like and care for Billy, and would rather be with him than Mandy since she always orders him about and uses him for her own selfish reasons.


Despite being his best friend Mandy treats him more like a servant than a friend; and never being one to pass up an opportunity take advantage of his stupidity, Billy his either is too dumb to notice this or actually doesn't mind at all and enjoys it even. Billy may take orders from Mandy a lot but it's most likey because he wants to do so and finds doing it fun; if it's an order that Billy does not want follow then he will not obey her command at all, like not handing over whatever supernatural and dangerous object he is causing trouble with despite being told by Mandy to do so.

Billy may have romantic feelings for Mandy whether or not he actually realizes it, and has suggested marrying her at least three times; for instance he seemed eager to marry her in the episode "Keeper of the Reaper" when Judge Roy Spleen initially mistook the trial for a wedding ceremony, he has also hugged and kissed Mandy a few times throughout the series and she doesn't tend to get too upset with him for it either.

Billy has protected Mandy as well for example in the episode "Little Rock of Horror"; when he tried to keep her from getting her brain sucked out of her head and eaten from the alien-meteor,even though she got her brain taken away in the end. Despite mostly treating Billy with contempt Mandy seems to genuinely care about him; she has protected and rescued him many times throughout the series, and he is the one person she actively hangs out with on daily bases. However it's uncertain if Mandy's feelings for Billy are strictly platonic; or if they are indeed romantic but just concealed for the sake of her image and reputation, also Grim sometimes teases them about it aswell by pairing them up together.


Billy gets along with Irwin more than anyone else. The two boys’ both have much in common, they both enjoy activities which are typically nerdy. But they are also extremely different; although Irwin has his moments of stupidity, he is also very smart, and is a 'math nerd' and 'socially inept' according to Mindy.


Jeff believes that Billy is his father, unfortunately for Billy, since he's extremely arachnophobic. Billy found Jeff's egg in Grim's trunk, and since Jeff saw Billy first when he hatched from his egg, he imprinted on Billy as his parent. Since then Jeff has done everything possible to win his "dad"'s love. However, no matter how good of an arachnid Jeff is, one who anyone else would be proud to call "son", spider or not, all Billy can see is a disgusting monster, which he beats at every possible opportunity. But by the end of the series he has gotten over this, and accepted the love of his "son". In the end credits of Billy and Mandy: Wrath of the Spider Queen,

Billy and Jeff are spending time together, and Jeff expresses his joy that Billy has finally accepted him "not only as a son, but as a spider." Billy, suddenly remembering that Jeff is a spider, begins to beat him with a stick, though as usual, Jeff fails to notice the hatred in it.


Billy's small pink cat. Billy loves Milkshakes.

Mr. Snuggles

Billy's elderly 10 year old hamster. Mr. Snuggles's cage is kept in Billy's room. It was through Mr. Snuggles that Grim became Billy and Mandy's best friend forever.

Fusion Fall

In FusionFall, During the war, Billy adopted a Fusion Spawn named Runty, which later turns out to be his imaginary friend. Most of Billy's missions are rather pointless, but sometimes lead to more important tasks: Once Billy had the player retrieve Irwin's stuff, so that he may "watch it". Other times he had the player collect food and cage lining for Runty, in doing so revealing Fusion Mandy's lair in the Sand Castle. In his own self interest, Billy sent the player out to remove the Re:Fuse posters found in Habitat Homes after being paid 20 bucks to do so by the leader of the Beautification Organization, Fusion Father. Little did he know that in doing so, he caused the local Fusion monsters to return to their normal destructive selves. Due to his fear of clowns and nightmares he'd been having, Billy has the hero go south to City Point, in order to defeat the Destroyusalls. He then has you collect their noses, but Billy thinks the noses are scary, so the hero gives the noses to Bloo. Billy also tricked the player and stole his/her power of destiny, which allowed him/her to activate totems, just because he thought it was cool. Soon following Billy's attempt was Hex, who was unaware that Billy already stole the player's power. However, Mandy gives the player the Pillow of Common Sense, a strange pillow that actually took back the player's ability from Billy by smacking him with it and Mandy returns the player's powers to him/her (saying that she could have kept the powers herself but decided she already had common sense). In the last attack on a Fusion Control Center, Demongo planned to have Eduardo join the hero to provide an assault of Imaginary Energy. Billy showed up instead, thinking that the Control Center was the site of a party. He later showed up in Fusion Kevin's base under the same premise. This time however, he was able to make himself useful by overloading a force field made from imaginary energy stolen from Foster's Home, allowing the player to defeat Fusion Kevin which proves Billy is not that dumb.


Billy's Damomdy
The image gallery for Billy may be viewed here.


Billy FusionFall

Billy in FusionFall

  • Billy is one of the many characters in FusionFall.
  • He also has questionable schizophrenia, indicated in Bearded Billy when he overhears his father in the bathroom and tells his mother, "the bathroom is talking to me again," and asks her for his "vitamins".
  • In The Crawling Niceness, it is revealed that he is afraid of spiders.
  • Billy may have been responsible for Irwin's crush on Mandy; in the episode "Get Out of My Head!", he flirts with Irwin while in Mandy's mind, causing Irwin's emotional state to switch from frightened of Mandy to smitten by the remarks that Billy (in Mandy's body) makes. This could be why Irwin has a crush on Mandy, as it had not been established until then.
  • Maxatomar Ben 10

    Maxatomar from Ben 10

    An alien in the Ben 10 series is based on Billy. The alien is orange, scaly and bloated with a large orange and pink nose, pointed ears and bad teeth. It is voiced by Richard Steven Horvitz and wears a blue and white striped shirt, and a red hat. It's species is named the Maxatomar (named after Maxwell Atoms).
  • His scientist uniform in Underfist: Halloween Bash is an allusion to Dexter from the TV series, Dexter's Laboratory.
  • In "Attack of the Clowns", It is revealed that he is afraid of clowns.
  • Billy's intelligence can also affect reality (similar to Mandy's smile) in "Billy Gets an "A"
  • Billy's nose is removable, on one occasion even growing back after coming off.
  • Also similar to Mandy, who is mistaken for a boy on more than one occasion, Billy has been mistaken for a girl.
  • It was confirmed in The Nerve that Billy had a brain, but as little as an ant.
  • In Billy and Mandy's Big Boogey Adventure, it is revealed that he had three fears: spiders, clowns and the mailman. He has an extreme fear of the Spider-Clown Mailman.
  • He is Mandy's boyfriend and quite posibbly fulture husband.
  • Billy maybe older than Mandy since his birthday party was celebrated in the 7th episode 'Tastes Like Chicken'; and her party was celebrated in the episode 9th episode 'A Grim Surprise', even though her actual birthdate was not for another "5 months."
  • In the Holiday special episode "Billy and Mandy save Christmas"; it was revealed that Billy celebrates Hanukkah, making him and his family Jewish.
  • He is clearly a type "B personality"
  • A lot of the episodes consist of Billy ending up in some sort of peril of predicament; either because of his own foolishness or just his bad luck, and Mandy and Grim always having to go after him for a resuce.
  • He's only called by his full first name, William, in two episodes. "Smarten Up" and "The Bubble with Billy".



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