King Boo is bigger and larger than the average Boo. In the first game he ever appeared, he had menacing red eyes, purple ruby on top of his head, black eyelashes, sharp fangs, and blue tongue. His modern look is similar to his original look, but wears a golden crown that resembles Princess Peach's, less menacing-looking black eyes, and his tongue is now pinkish-red. His fangs are still the same as original.
His first game was in Luigi's Mansion as the main antagonist, where he traps Mario in a painting, and plans to do so with Luigi. Luigi has to defeat King Boo with his Poltergust 3000, which will suck up any Boo. In the final fight with King Boo, he is actually piloting a giant Bowser mecha, and when he comes out, that's your chance to harm him.
He also makes many other appearances such as a boss in Super Mario Sunshine, Super Mario 64 DS and Super Princess Peach, a playable character in Mario Kart: Double Dash‼, Mario Kart Wii and Mario Superstar Baseball., and as a challenging boss in in the fourth level in mission mode of Mario Kart DS.
In Luigi's Mansion, he is the size of a regular Boo, if not slightly bigger, has a bigger mouth with vampire like fangs, and a ruby crown on his head, but in Super Mario Sunshine he is much larger and wider then he was in Luigi's Mansion and has tired eyes, and a huge, long tongue coming out of his mouth. His battle is in Hotel Delfino's Casino. In Mario Kart: Double Dash and other games he looks more like he did in Luigi's Mansion, only with different colored eyes and a different crown.
He also appears in Luigi's Mansion: Dark Moon once again as the main antagonist, where he once again traps Mario in a painting, as well as shattering the Dark Moon in evershade valley. His appearance is more similar to his Luigi's Mansion appearance, except he still has a full row of teeth like his modern appearance instead of his vampire like fangs in Luigi's Mansion, he also speaks with his sped up voice in the modern Mario games.
In the Mario Kart series
King Boo is an unlockable character in the racing game Mario Kart: Double Dash!!. This is his first appearance in a spin-off, and also his first playable appearance, resulting in further appearances in the Mario Kart (series). King Boo is classified as a heavyweight driver due to his large size. His partner is Petey Piranha, and both have the ability to use almost any other character's special item (if they are going to get a special item, it is randomly chosen, based on their race position) but they can not receive the Green Fireball or the Birdo Egg.
King Boo makes a cameo appearance in Mario Kart Arcade GP 2 on the Yoshi Park 2 course. Here, a large picture of him appears near the end of the course where it inhales many ghosts and the racers. As the player drives into his mouth, they are warped back to the beginning of the course.
King Boo appears as a boss in Mario & Luigi: Paper Jam, making his official Mario & Luigi series debut. He is encountered and fought in Gloomy Woods after the trio separate, leading to him kidnapping Mario and Paper Mario; leaving Luigi alone to find them, like in the Luigi's Mansion series. After finding Mario, he and Luigi begin to look for Paper Mario. They eventually find King Boo instead, disguised as Paper Mario. After his true identity revealed, King Boo engage the bros in battle, once defeated, Paper Mario is reunited with the duo and the group continue their travel to Mount Brrr.
|Item Drop||Guard Wear DX (100%)|
Boss Battle Ring
- In Mario & Luigi: Paper Jam, King Boo's voice clips from Mario Kart Wii are reused.
- in Mario Kart Wii King Boo is one of very few characters to have his standing animation on the Character Select screen altered from Mario Kart: Double Dash!! In this case, his tongue is not sticking out of his mouth the whole time like before; now, before selecting him, his tongue is still in his mouth.
|Main characters||Mario • Luigi • Princess Peach • Toad • Yoshi • Paper Mario|
|Supporting characters||Dr. Mario • Princess Daisy • Rosalina • Donkey Kong • Diddy Kong • Pauline • Professor E. Gadd • Toadette • Toadsworth • Captain Toad • Birdo • Nabbit • Cappy|
|Enemies||Bowser • Bowser Jr. • Koopalings (Larry Koopa / Morton Koopa Jr. / Lemmy Koopa / Wendy O. Koopa / Iggy Koopa / Roy Koopa / Ludwig von Koopa) • Wario • Waluigi • Fawful • Kammy Koopa • Dimentio • Antasma • Kamek • King Boo • Petey Piranha • Tatanga • Wart • Foreman Spike|
|Luigi's Mansion characters|
|Allies||Luigi • Professor E. Gadd • Mario • Toad • Polterpup • Gooigi|
|Portrait Ghosts||Biff Atlas • Bogmire • Boolossus • Chauncey • Clockwork Soldiers • Floating Whirlindas • Henry and Orville • Jarvis • King Boo • Lydia • Madame Clairvoya • Melody Pianissima • Miss Petunia • Mr. Luggs • Nana • Neville • Shivers • Sir Weston • Slim Bankshot • Spooky • Sue Pea • Uncle Grimmly • Vincent Van Gore|
|Major villains||Donkey Kong | Bowser | Foreman Spike | Wart | Koopalings (Ludwig von Koopa | Lemmy Koopa | Roy Koopa | Iggy Koopa | Wendy O. Koopa | Morton Koopa Jr. | Larry Koopa) | Tatanga | Virus | Wario | Kamek | Baby Bowser | Smithy | Big Bob-omb | Waluigi | King Boo | Shadow Mario | Petey Piranha | Bowser Jr. | Cackletta | Fawful | Antasma | Sir Grodus | Lord Crump | Shadow Queen | Princess Shroob | Count Bleck | Dimentio | Pom Pom | Boom Boom | Bowser Soul | Topper | Hariet | Rango | Spewart | Madame Broode|
|Minor villains||Blooper | Bob-omb | Boo | Bullet Bill | Buzzy Beetle | Chain Chomp | Cheep Cheep | Dry Bones | Goomba | Hammer Bros. | Koopa Paratroopa | Koopa Troopa | Lakitu | Magikoopa | Monty Mole | Ninji | Piranha Plant | Pokey | Shroob | Shy Guy | Snifit | Spiny | Thwomp | Whomp | Wiggler|