Billy & Mandy's Big Boogey Adventure was the first made-for-TV movie of The Grim Adventures of Billy and Mandy.
The plot storyline is that Billy, Mandy, Irwin and Grim must save the Earth from Boogeyman's attempt to steal Horror's Hand to take over the world outside the center of the Earth in a competition started by Horror the Ancient. There are two teams competing, The Grim's Reaper's Team consists of Billy, Mandy, Irwin, and Grim. The Boogeyman's team consists of Boogeyman, Fred Fredburger, Dracula, Creeper, Billybot, Mandroid, and several army slave pirates.
Endsville, two weeks in the future. The shadowy all powerful "Lord of Horror", possessor of Horror's Hand, sends robot replicas of Billy and Mandy (called Billybot and Mandroid) to the present. They are to stop the two from obtaining the Hand. Future Irwin and Billy watch. Billy was going to go to the present himself but had been too distracted by the opening credits. His back up plan, another time machine, is in reality, a drawing of policemen fighting a dinosaur (likely a Spinosaurus).
In the present, the Grim Reaper travels next door to take the soul of General Skarr, who now has a huge gaping hole in his stomach. Skarr doesn't wish to go and he manages to escape in his vehicle, which has many weapons (this may be a parody of Spyhunter). These weapons delay a pursuing Grim (and present-day Billy and Mandy, who had decided to ride along). Skarr finally escapes by transforming his vehicle into sub form. He sees another button and presses it, curious. A laser blasts out, straight through the hole in his stomach. Skarr realizes what had happened.
Back at Billy's house, the Underworld Police take Grim away for the crime of abusing his powers. The courtroom is in a more hellish-locale. The jury is split up in pairs and each pair sits atop a giant pillar. The jury includes Dracula, Frankenstein’s Bride, Wolf man, Fred Fredburger, a Pale Ghoulish Juror, a mud ghoul, Darth Vader, The Invisible Man, and two unknown citizens. To everybody’s surprise, Boogeyman is the prosecutor and is suing Grim for abusing his powers. Boogey mentions the following people stole Grim's scythe:
- Jack O' Lantern
- Billy's Father
- Billy's Mother
- Billy's cousin (Not Junior)
- Milkshakes (Boogeyman said Billy's Cat)
- Principal Goodvibes
- The Secret Snake Club
- General Skarr
- Mrs. Claus
- The Army
- Scout Troup 7-0-1
- The Sleestax
- The President
- The Mailman
- The Dingle Schmidt Sisters
- The Boogey Man (himself)
- A llama
- And a turkey salad sandwich!
In the end, Grim is found guilty and the Boogeyman agrees to take him and the kids to exile while Numbuh Three from the Kids Next Door temporarily becomes the new Reaper, on a six week trial. Numbuh Three claims that she is using the Rainbow Monkeys' Association Power to take over the world with a cold, iron blade and seems to enjoy her job (in reference, Grim said "Who's going to replace me, huh? The Kids Next Door? Hey come on, I know my rights!")
Boogey’s ship makes it way to the Lava Sea where Boogey plans to feed the children to Lava Sharks. Boogey reveals his plot to steal Horror’s Hand the most powerful object in existence which makes Grim's scythe look like a worthless stick and if you go too near it you will be confronted by your worst fears but if you conquer your fear you can get it. The hand is capable of transforming its holder into the scariest and most powerful being in existence. Boogeyman sends Billy first to walk the plank. Billy reveals that he’s not scared as long as the sharks don’t eat them and starts a song called 'Scary-O.' Along with the song, Mandy and the rest of the captives make a run for it. Billy sings the song about how he’s not scared of earthquakes if the earth doesn’t shake and at the end of the song, he briefly sings about how he’s hungry. Irwin, Mandy, and Grim make a run on the getaway boat, the "deathboat" (obvious reference to a lifeboat). Billy comes along and Mandy asks what he was doing, Billy responds saying that every animated movie needs a song. Mandy sees Boogey dancing and says, "Now that’s scary."
Boogeyman is first to go through the gate to Horror’s Hand and claims that Billy and Mandy must go through the Cyclops to go through the gate. The group decides to stop Boogey and claim Horror’s Hand. Mandy wants to rule the world with the hand, Billy wants to buy food, Irwin wants to marry Mandy with the hand, and Grim could reclaim his role as Grim Reaper and get his scythe back. Grim then plans to use is powers to transform the boat, only to remember he lost it. The group meets a little Cyclops with no eye who calls his friend, a giant orange Cyclops to "test" the children. This test is however revealed to be tasting the children by the Cyclops which they "pass", ending up cooking in a giant soup. Mandy, in an attempt to escape, claims that Billy urinated in the soup (which he in fact did) so the Cyclops takes them out to check. Mandy uses the opportunity, jumps out and steals the bigger Cyclops’ eye. There is a fight and the eye ends up in Billy’s stomach. It turns out that the eye is used also for Boogeyman to see the group. Boogeyman turns his head into disgust as he looks where the eye goes. Creeper offers to build robot replicas of the children and shows Boogeyman the blueprints. Suddenly, Mandroid and Billybot from the future appear and offer to help Boogeyman destroy Mandy and Billy.
The group run away from the Cyclops Cove and discover a giant cake as they run near the getaway ship. Mandy is suspicious but a crazy Irwin and Billy stuff the cake into Mandy and Grim’s mouths. Suddenly, the rest of the group fall into a sleep and Mandy soon follows into the trance. Inside the cake, Mandroid comes out of the cake’s hatch and reveals that she plans on taking the brains of the group. The group is having a hive mind dream (Numbuh Three shows up again and disguised herself as a horse Billy is riding) when Boogeyman comes in and kidnaps Mandy. Meanwhile, Mandy was on the ship's pole tied up being the Boogeyman's prisoner while put under his spell making her sleep until her spirit is broken. The Boogeyman laughs as a mad Irwin storms in and beats up all the pirates. Grim tells Billy that love makes people do stupid things. Billy reveals that he loves everything and Grim says that, that explains a whole lot. Irwin kisses Mandy awake to Grim’s and Billy’s utter disgust. Mandy is grossed out and vomits twice. Mandroid comes in and threatens with a laser gun. Mandy is disgusted by how unrealistic Mandroid is and causes Mandroid to malfunction. Mandy takes the laser gun and shoots a stalactite down stopping the pirates from attacking and the group makes a run for it on the deathboat and goes in the lead to Horror’s Hand’s Temple. Boogeyman sends the Kracken to go after the four.
The group climbs up the long stairs of the temple. About halfway up, Billy claims he can see his Grandmother's house from this vantage point. The others do not believe him and move on. Billy waves to his grandmother down below and follows, but he can't understand why she moved there. Horror is a living ancient God who resembles Mercury. He had explained to Team Grim that long ago, he cutted off his left arm so he would be bold and brave forever. Billy asks if cutting off his left arm was really what made him brave. Horror responds with a very negative phrase Oh, thank goodness, no, I mean, what was I thinking? First of all, I was a lefty, so once I cut it off, I couldn't sign my name! Then I just got bored and now I do a lot of online gaming and learned to play the guitar with my teeth. Boogeyman's forces appear and Billy is soon eaten by the Kracken. Boogey decides to hold a river race called the Cannibal Run. The winner will have to fight Horror for the right to the hand. Grim's very small boat seems unwindable next to Boogey's legged ship. The two sides prepare. Billy hasn't resurfaced yet and Mandy thinks he might actually be dead this time. Billy appears, having made friends with the Kracken.
The race starts. Throughout it, the team become puppets, destroys a sea witch with laser guns, glue their boat back together with snot after its cut to pieces, and even get attacked by Japanese movie kaiju (Godzilla, King Ghidorah, Anguirus, Rodan, Gigan and Gamera). After all that, Team Grim wins and easily defeats Horror with Mandy tearing off Billy's nose and throwing it at his head. The group tries to face their worst fears, as Billy faces a clown spider mailman (or is it a clown mail spider), Irwin faces stand up comedy jokes to bears, and Mandy faces an older version of herself who has lost her toughness , overweight, and married to Irwin. But Grim is the only one who conquers them as he lives his nightmare every day: living with Billy and Mandy. After Grim picks up the hand, Boogeyman steals the hand - but is defeated by his worst fear: discovering that he’s not scary and getting laughed by everybody. Grim later reveals that he turned the Hand off and Boogeyman now is living his life in his fears. The police come in and Judge Roy Spleen tries to banish Grim, but Mandy threatens the Judge so he decides to give Grim his job back and fire Numbuh 3 (although he remarks that Numbuh 3 was a great reaper in her own way). Numbuh 3 vows to get revenge on Grim if it’s the last thing she does, but later forgets and laughs a innocent laugh away.
When Fred Fredburger says that "If I hadn't tried to eat all of the nachos, I never would have known I could", the team learns a valuable lesson: that they got what they wanted without having the Hand. Grim saved the world even without the scythe, Mandy got her own way once again, Irwin finally got to kiss his true love, and Billy is getting a new bike for Christmas. To everybody’s surprise, future Billy teleports into the temple and reveals that in the future Mandy stole the hand and become Lord Horror the supreme master of existence, just as Mandy gets hypnotized by it and seeing future Billy, nude, makes her trance go away. Mandy merely shrugs and hands the hand back to Grim. Grim is forced to put the Hand somewhere. Grim decides to put the Hand in his trunk. The group returns home with future-Billy saying his farewells. Billy asks what he’s going to have for lunch next Tuesday and future Billy says, “I could tell you but then I would have to kill you." Mandy orders Grim to make dinner. Meanwhile, Billybot and now more realistic Mandroid order their own servant, Creeper to serve root bear.
The ending credits shows the future of what the characters each have had:
- Grim went back to fighting supernatural toilet clog monsters with his scythe (mentioned during the Court Trial)
- Mandy became the new Captain of the Boogey Bay
- Billy became President of the United States
- Irwin caught mono and cooties from kissing Mandy
- Billybot and Mandroid transformed to fight crime. (Parodies Transformers)
- General Skarr puts good use to the hole in his body by making it a birdhouse hole.
- The Krakken was arrested for 8-armed robbery (for eating the seagull earlier in the film)
- The Cyclops got their own show (they have now lost their eye still, but are now experts in being blind).
- Horror became a Rock God.
- Creeper made a fortune selling time-traveling pants (to cavemen).
- The Boogeyman lives in his fear to this very day and locks himself up in his room every day.
- Numbuh Three set up her own reaper service, 25 cents for one person's soul, but becomes a failure and laughed at by everyone. This character credit is used in the animation style of Codename: Kids Next Door while we see the words "Hee-Hee" and Ha-Ha!" with fingers pointing at Numbuh 3.
- Hoss Delgado did not appear in the film, so he watched the film all on TV while eating chocolate ice cream.
- Grim's scythe was stolen again by Dracula (again) while he plays golf now.
Mandy, Billy, General Skarr, The 2 Cyclops, Horror, and Creeper got good luck. The Krakken, The Boogeyman, Numbuh Three, and Hoss Delgado got bad luck. Grim, Billybot, Mandroid, and Dracula got neutral luck.
After the end credits, future Billy returns to his time to see if the world is still normal. However, he discovers the world is still enslaved by techno robots to see everyone in line and millions of human skulls are laying on the floor. He is grabbed by two robots, and wonders who could have done it by stealing Horror's Hand. He finds the Lord Horror, crying out, "I should have known! It was you!!", and we see that Fred Fredburger was Lord Horror when he overcame his greatest fear: running out of nachos. He spells nachos N-A-C-H-O-Z with his flying nacho dispenser and says his cite "Yes!"
The DVD was released on April 3, 2007. The DVD contains both anamorphic widescreen and modified fullscreen versions with 5.1 surround sound and regular stereo sound. Special features include the original "Bully Boogie" episode and interviews with the voice actors.
As of 2022, there are seldom plans for this movie to be reissued on any format due to music licensing issues.
- Grim: The protagonist of the film, the Reaper of Endsville, who lost his powers after Boogey Man successfully sued Grim in a lawsuit and stripped a power that Grim always loved and carried with: his scythe. Together, he must get Horror's Hand with really spoiled children for his job back.
- Billy: A stupid and extremely-illiterate boy who has disgusting nose powers and tries to show the moral all the time, even if everyone already know.
- Mandy: An arrogant and evil girl who never smiles, laughs, cries, and has no nose. She wishes to use Horror's Hand to take over the world herself.
- Irwin: A nerd who has an unhealthy crush on Mandy, realizing the power of love, but always gets bad luck no matter how hard he cries.
- Boogey Man: The primary villain and antagonist of the film, who sets out to reach Horror's Hand with his giant crewship and Creeper.
- Creeper: The green henchman of Boogey who invents Billybot and Mandroid, obeying all his orders. He is a parody of the Marvel character Felix Faust.
- Kuki Sanban: A very happy-go-lucky and kind operative of Sector V who wants to be the Reaper for unknown reasons.
- Fred Fredburger: A green elephant monster who lives in the Underworld and joins Boogey Man's ship mistaking it for a cruise to the Grand Canyon.
- Horror: An ancient god who cutted off his hand so he would be bold and brave, but later wished he never did.
- General Skarr: A retired army general from the show Evil Con Carne who has a very large anger management problem.
- Harold: The father of Billy, who acts like him, and gets fired from every job in at least one week, especially the last job at Freckleburger.
- Gretchen: The mother of Billy, who never has a moment without any stress, and gets angry about everything with Harold and Billy all the time.
- Billybot: A robot version that is a blueprinted image created by Creeper, who has a hard time not being able to pee since he's a robot.
- Mandroid: A robot version that is a blueprinted image created by Creeper, who assimilates and takes orders from anyone, but later reverses traits.
- The Gatekeeper: A clumsy orange cyclops monster who enjoys cooking with cinnamon, and fights with his butler who uses proper English unlike him.
- Dracula: A vampire who is Irwin's grandfather and lives with a lot of other monsters, talks extremely fast, and defends why Dragon acts so dumb.
- Judge Roy Spleen: A arrogant and egotistical judge who hates everyone and was angry to everybody at least once, complaining about them.
- Hoss Delgado: A monster-hunter who has only one eye and one arm, barely being a normal guy, & was absent in the film, but not in the credits.
- When Boogey tells his assistant, Creeper, to summon the kracken, it is an obvious reference to the Disney film, Pirates of the Caribbean 2: Dead Man's Chest where Davy Jones sends his kracken out to hunt down Captain Jack Sparrow and then later Will Turner. And the fact that Boogey's ship has black sails may also be a reference to the Pirates trilogy due to the Black Pearl also having torn, black sails.
- When Billy, Mandy, Irwin and Grim are about to be eaten by the cyclopes, then take his eye and cause Billy to eat it, is a reference to the Greek story of Oddessius where Odessius and his men are trapped in a cyclops's cave and Oddessius and his men blind the cyclops and trick him into letting them go.
- The keys that Creeper uses to release the Krakken makes a sound of the car key vibration to open the headlights of a sedan.
- The characters from the show Sperg, Mindy, Pudn, Miss Butterbean, Nigel Planter and the rest of the Harry Potter parodies, Nergal, Nergal Junior, the parents of Mandy, Mandy's dog, Irwin's parents, and Billy's aunt do not appear. It should be noted that The Secret Snake Club and Mrs. Claus would have been marked absent if they were not mentioned in the very long list Boogeyman shows with a clip show picture of each who stole Grim's scythe. Also, the special characters Hoss Delgado (referenced in the ending credits) and Jeff the Spider do not appear.
- The guitarist shown playing the solo in the song Scary-O resembles Slash, the guitarist of the band, Guns and Roses. He has long hair and the signature top hat with medals on it like Slash does.
- The scene where Irwin made Mandy wake up from a disgusting kiss references Sleeping Beauty after defeating several pirates.
- Irwin said "This is just like Titanic!", referencing the suicide part.
- Irwin finally kissed Mandy in this film, which he always wanted to do in the TV Series. However, the ending credits stated he caught cooties and mono after he did this act.
- The picture where policemen are fighting dinosaurs is a parody of the 1997 film The Lost World: Jurassic Park, where several police cars chase after a Tyrannosaurus Rex rampaging loose in San Diego brought by ship transport. The dinosaur the cops are fighting is a Spinosaurus, the major antagonist of the film Jurassic Park 3.
- Boogey's ability to morph into objects is absent in the film, which he had in the TV Series.
- According to Tom Warburton, the creator of Codename: Kids Next Door, he first wanted to use Numbuh 2 as the Reaper in the film, but he ended up with & having Numbuh 3 as the Reaper, since she is the only Sector V Operative who has an antagonistic side. The film changed almost 100% of Kuki's personal attitude and personality.
- At the beginning when Grim comes to reap Skarr you see through the hole in his chest, but you should actually see the robe he is wearing. However, it is possible that he was wearing the robe when the laser that created the hole first shot through him.
- During the car chase, you can see that the gas pump doesn't hook to anything but in the end it hooks to the firework store and Hot Fudge truck.
- In the episode, "Bully Boogie", Boogey was sent to the Pit of Terror, but Mandy asks, "Didn't we banish you to the Nightmare Realm?". This is also referenced in the video game as Boogey's criminal record of being banished there for impersonating a TV (another "Bully Boogie" reference).
- The DVD subtitles say that General Skarr said damn.
- When Boogey's ship flies up to the summit of The Isle of Peril, nothing is on the bottom. But during the Cannibal Run, a sea monster is revealed to be fused with the ship.
- When Boogey opens the back window asking if the gang could fly near the falls, the window is a full door, but as he tells Creeper to activate the rockets, the window has two little doors.
- Boogeyman left out Nigel Planter and The Time-Year Man who is with Baby New Year of the list who stole Grim's sword.
- As the gang gets over the falls using Grim's cloak and gaining the lead, in the next scene the snot covering the ship disappears.
- When Grim was about to punish General Skarr, he doesn't have his scythe. When he comes out, his scythe is seen immediately in his hand-bones.
- When Billybot eats the cannon, he seems to have put it in a storage portal of some sort. But when he drinks root beer in two scenes, he seems to have a normal robot mouth.
- When Irwin goes to the ships deck to save Mandy, the cannons are lined diagonally. But when Boogey loads the cannons, they're all straight in a line.
- This whole film was available on Cartoon Network Video until November 24, 2008.
- Horror said that he had gained 20 pounds, even though he's about more than 10 times the size of a human and still considers himself overweight.
- When Billybot says "I like pie!" in the movie, the DVD subtitles say that he said "I am high!". When Billy says "freak out gland!" in "Scary-o" the DVD subtitles say that he said "freak out band!" and when Billybot says "I am dreaming that I am a pygmy marmoset!" the DVD subtitles say that he said "caky marmoset!"
- Horror's Hand has 5 fingers like us but all the characters have only 4 fingers. So none of the characters could hold his hand so easily.
- In the Cannibal Run map, you can see that the Skull Rock has been cut from film and a brand of river lead to Camden, New Jersey.
- In the end, 15 Underworld Cops come out of the vortex, but when they disappear there's only 13 of them.
- When Boogey takes the picture with Grim, his eyes are open but in the picture, his eyes are closed.
- When Billybot first says "Query: why are we hunting Billy and Mandy?", the subtitles read Larry why are we hunting Billy and Mandy.
- Before Billy sees his grandma on the steps to Horror, in one scene, the group can be seen walking over an outline of stairs, not stairs themselves. Also, it should have been boards, not stairs.
- The "It's just a flesh wound" remark was made in Richard Donner's film Lethal Weapon 3 when Murtaugh tells Leo he won't die after he was shot by a hollow point bullet on a hockey rink.
- At some shots, Grim's boat could be behind or in front of Boogeyman's ship at times.
- If Mandy threw Billy's nose at Horror, then what happened to have Billy have another nose?
- When General Skarr is fleeing The Grim Reaper, we see a squirrel with gathered acorns ran over by the car Skarr is driving. When Grim chases after him, the sword cuts the squirrel in half. However, it should have separated the squirrel's eye, nose, mouth, half of belly, and one leg from the other eye, nose, mouth, half of belly, and other leg. Instead, the squirrel's belly was cut off in latitude in it's body. Good thing he was okay!
- Episodes like The Secret Snake Club Vs. PE and Billy & Mandy Save Christmas are referenced in this film.
- Billy & Mandy's Big Boogey Adventure was met with highly positive critical reaction, with the gooey humor and colorful singing.
- Land of the Dead: by Voltaire
- Scary-O: performed by Billy and the Pirates, written by Maxwell Atoms and Gregory Hinde
- Boogie Wonderland: by Earth, Wind and Fire