King Boo

King Boo in the final battle of Luigi's Mansion
King Boo
Species	Boo
Eye color	Red or Black
Voiced by	Toru Asakawa
Debut	Luigi's Mansion

King Boo is a recurring enemy from the Super Mario series who is the leader of the Boo forces and a minion of Bowser. He has notably acted as the main villain of Luigi's Mansion and its sequels, as well as appearing as a recurring boss character in Mario games. He has had design variations depending on his appearance: in the Luigi's Mansion games, he has a more sinister appearance with red eyes and a crown containing a large ruby jewel, while his Mario appearances instead depict him as resembling a standard black-eyed Big Boo wearing a generic crown. This has bred some confusion about whether they are all the same character or if there are different incarnations of King Boo.

Background

Super Mario 64 DS

King Boo appeared as a boss in Super Mario 64 DS, but he was not identified by name in this appearance. He appeared to be a Big Boo wearing a crown, and he could be identified by his laugh (which was the same as his laugh from Luigi's Mansion). King Boo's area was hidden within Big Boo's Haunt, and King Boo had to be defeated by Mario in order to free Luigi. In battle, King Boo was invisible to Mario, but his reflection was still visible in the room's mirror. By observing this, Mario could follow King Boo's movements and attack him, with Luigi appearing as Mario's reflection in the mirror. Mario had to pound King Boo three times to defeat him.

If the game is considered a retcon of Super Mario 64 and takes place before Luigi's Mansion, than this boss battle could be seen as the root of King Boo's grudge with the Mario brothers.

Luigi's Mansion

King Boo was the main villain of Luigi's Mansion. In this game, he was depicted with red eyes and wearing a jeweled crown (which he referred to as a power-enhancing device in the sequel). King Boo freed the ghosts from Professor E. Gadd's Gallery and then combined his powers with those of his Boo followers to create a fake mansion which looked like it had been around for quite a long time. King Boo then sent a letter to Luigi telling him that he had won the mansion in a contest. King Boo succeeded in capturing Mario when he came to check out the mansion, as revenge for the trouble that Mario had caused him in the past, but he did not expect Luigi to join forces with E. Gadd against him. Armed with the Poltergust 3000, Luigi sucked up the mansion's ghosts until only King Boo remained.

In the final battle, King Boo attacked Luigi on the mansion's rooftop from within what appeared to be a giant version of Bowser. Luigi was able to face his fears and forced King Boo out of the decoy Bowser's body long enough to suck him into the Poltergust. This caused the mansion to disappear, and King Boo himself was turned into a portrait in E. Gadd's gallery. According to an offhand comment by E. Gadd in the sequel, Gadd later sold that portrait at a garage sale, which paved the way for his eventual escape.

Later Appearances

King Boo's goofier look from Super Mario Sunshine

In Super Mario Sunshine, King Boo appeared with a goofier design. This included a sagging tongue, drool running down his mouth and differently-colored eyes. As in most of his non-Luigi's Mansion appearances, he also wore a pointed crown instead of a jeweled one. Within Sunshine, King Boo acted as the boss of Sirena Beach's Hotel Delfino. Mario could defeat him by throwing spicy fruits at him. As many enemies in the game were formed out of goop by Bowser Jr., that could explain this appearance's differences from other depictions of King Boo.

King Boo also appeared as boss of the Shriek Mansion in Super Princess Peach, where he was formed by a merger of three Boos and guarded a captured Toad. He attacked by sending out blue flames, and to defeat him Princess Peach had to light all of the lanterns in the room several times. Every time all of the lights were ignited, King Boo would be damaged and would begin crying more often as he lost more health, until he was defeated. The aversion to sunlight in this game was notably contradicted by King Boo's other appearances.

He acted as the main antagonist again in Luigi's Mansion: Dark Moon. In another attempt to gain revenge on the Mario Brothers and E. Gadd, King Boo came to Evershade Valley. All of the valley's ghosts were friendly due to the power of the Dark Moon, so King Boo proceeded to shatter the Dark Moon and corrupted its shards, which made the ghosts turn hostile. He organized those various ghosts and Boos under him, and he mined for special crystals to enhance their power. He also captured Mario and imprisoned him in a painting again. Luigi finally encountered him at the last area of the valley, the Treacherous Mansion. King Boo hid within a portal to another dimension and battled Luigi after he had claimed the last Dark Moon shard. King Boo unleashed a variety of attacks during their battle, but he was ultimately defeated and captured again. King Boo was also faced during the final battle of Luigi's Mansion Arcade, which followed a truncated version of the story of Dark Moon, but featured a different attack pattern for King Boo.

In Mario & Luigi: Paper Jam, King Boo battled the Mario Bros. and Paper Mario at the Gloomy Woods. First, he captured both Mario and Paper Mario. Luigi was able to find Mario, at which point King Boo transformed into Paper Mario to trick them. They eventually saw through his disguise, at which point they fought each other. During the battle, King Boo attempted to get Mario and Luigi to stop attacking him by having a Paper Boo hold Paper Mario hostage, but Paper Mario could be freed by defeating the minion. King Boo was ultimately defeated. A Papercraft version of King Boo also appeared earlier in the game, and it was used by Lemmy and Morton at Bowser's Castle.

The Switch Era

King Boo returned again in Luigi's Mansion 3. Hellen Gravely lured E. Gadd to her hotel, The Last Resort. There, she trapped him in a painting and set all of his ghost collection free. This included King Boo, who she deeply admired. The power of King Boo's gem was implied to have been used to take control of the otherwise friendly local ghosts, and his power ended up helping the hold The Last Resort together as well. King Boo and Hellen soon set another trap to lure Luigi to the hotel with another fake contest, so that King Boo could get his revenge on him. He did not think that Luigi would fall for it, and yet Luigi accepted the invitation. That night, they trapped Luigi's guests (Mario, Peach and three Toads) in portraits, and King Boo cornered Luigi in an attempt to capture him as well. However, Luigi was able to escape through a laundry chute. He then found E. Gadd's latest Poltergust and freed Gadd himself. Luigi started to fight his way through each floor of the hotel. King Boo became disappointed with Hellen and took Peach's portrait to the rooftop of the building.

Luigi eventually freed the other captives and defeated Hellen. He then made his way to the roof and freed Peach from her portrait. It was then that King Boo struck. He plucked E. Gadd and the Toads from Gadd's portable lab, and he made a giant portrait that trapped everyone within it. However, Luigi was able to escape capture once again, and he proceeded to fight King Boo. In the ensuing battle, King Boo could be stunned by launching bombs into his mouth. While stunned, Luigi and Gooigi could combine the strengths of their Poltergusts to pull on King Boo's tongue and slam him around. After the first strike, he produced a clone of himself that fought with the same abilities. After being attacked again, King Boo tried sucking everything around him into the giant painting and summoned a third clone of himself. After being hit again, King Boo was successfully sucked up by the Poltergust. With his defeat, The Last Resort fell apart. His jewel also dissipated, which caused the local ghosts to become friendly and apologetic. King Boo was imprisoned within a capsule in E. Gadd's collection, alongside the capsule of Hellen, who continued to admire him from her new prison.

In Dr. Mario World, King Boo was initially made available as an assistant character starting in November 2019. He was available exclusively through battle boxes for players ranked Tier 7 or higher, and his effect could grant a chance of gaining extra capsules when growing low on capsules in Stage Mode, or came with a chance of sending extra rows of viruses to opponents in Versus Mode. He was later made available as a playable doctor character as well, as Dr. King Boo, starting in September 2020. In Super Mario Bros. Wonder, King Boo appeared in the Light-Switch Mansion level while the stage's Wonder Flower was in effect. In this appearance, he appeared on one side of the screen and began chasing the player character(s) with singing in an operatic baritone. When looked at, he would cover his face and sing with a distorted filter. Once the Wonder Seed was collected, King Boo would disappear in a puff of smoke and leave behind his crown, which fell into a pit. King Boo would later reappear for a part of the Wonder Flower segment in Bowser's Rage Stage with the same behavior, as the stage acted as a gauntlet of sorts for past level' Wonder effects.

In Other Mario-Related Games

Sports, Kart Racing and Party Spin-Offs

King Boo has made multiple playable appearances in the sports-based spin-off games of the Super Mario series, in addition to several appearances as a boss character. In most of these appearances, he resembles his design from Super Mario 64 DS.

• Kart Racing - He has appeared as a playable racer in Mario Kart: Double Dash!! (unlocked by completing the Star Cup on Mirror Mode and paired with Petey Piranha), Mario Kart Wii (unlocked by completing Star Cup in 50cc), Mario Kart 8 Deluxe, Mario Kart Arcade GP DX (during a limited event only) and Mario Kart Tour (where he could be obtained through the game's gacha feature or in-game shop starting in late October 2019). In Tour, the default version of King Boo used his design from his other Mario Kart appearances, but there was also a variant using his Luigi's Mansion design that was made available during certain tours. King Boo was depicted as a heavyweight racer in all appearances except for Arcade GP 2, in which he is instead a featherweight racer.
  • He also appeared as a boss character in the Mission 4 Boss Stage of Mario Kart DS, wherein Princess Peach had to collect 50 coins over a pit of lava, while he tried to steal them back. In Mario Kart Arcade GP 2, a large picture of him appeared within the Horror House of the Yoshi Park 2 course, which sucked up racers and warped them back by the starting line. In Mario Kart Live: Home Circuit, he was featured in the King Boo's Courtyard course that was added in a November 2021 update, and he could play a trick on the player when passing through the gate by temporarily flipping the screen upside-down.
• Tennis - In Mario Tennis Aces, he was featured in the Boo Hunt Co-op Challenge available within the game's 2.0.0 updated version. He appeared when Frenzy Time was active and had to be defeated with tennis balls.
• Baseball - He was playable in Mario Superstar Baseball and Super Mario Sluggers.
  • In the Challenge Mode of Mario Super Sluggers, he appeared in Wario City after Bowser Jr. was defeated there, having watched the battle while invisible out of curiosity to see who was stronger. He considered both sides to be "benchwarmers" and would only join the player's team if the Mini Boo had been found by the team.
• The Olympics - King Boo has appeared as a rival/boss in several of the Mario & Sonic at the Olympics games. In both versions of Mario & Sonic at the Olympic Winter Games, he could be raced against in different types of Alpine Skiing events. In Mario & Sonic at the London 2012 Olympic Games, he was faced in the Dream Sprint event within the London Party mode in the Wii version, while in the 3DS version, Sonic and Tails could face him and a Boo in a Badminton Doubles event. In Mario & Sonic at the Sochi 2014 Winter Games, he was raced against in Short Track Speed Skating 1000 in the Legends Showdown mode.

Mario Party

King Boo also appeared in Mario Party 8, as the host of the King Boo's Haunted Hideaway board. Like other hosts, King Boo would give stars in exchange for coin payments at his space on the board, but King Boo differed himself from other hosts by hiding himself out of plan sight and blowing all of the players back to the starting point after giving out a star. He continued to make appearances as a boss character in the following Mario Party games. He was faced at Boo's Horror Castle in Mario Party 9, the minigame King Boo's Tricky Trials in Mario Party 10 and the minigame King Boo's Light Smite in Mario Party: Star Rush. In Mario Party Superstars, he replaced the Big Boo found on the Horror Land board during nighttime and would send his Boos to steal Coins or Stars from other players after being paid with coins.

Cameos and Non-Storyline Appearances

• In Mario Golf: World Tour, King Boo made a cameo appearance floating with other Boos near a hole at the Bowser's Castle course.
• In New Super Luigi U, a sign in the shape of King Boo (with his Dark Moon design) could be seen at the Secret Exit of the Vanishing Ghost House. This marked a rare instance of the Luigi's Mansion design appearing in one of the Mario games.

Other Appearances

Video Games

• In the Super Smash Bros., King Boo has been represented by a trophy in Super Smash Bros. for Nintendo 3DS and as an Advanced-rank Primary Spirit in Super Smash Bros. Ultimate. King Boo's Spirit was created by enhancing the Spirit of a normal Boo that had reached Level 99, and his Spirit came with the effect of floaty jumps for the player's character.
• In Puzzle & Dragons: Super Mario Bros. Edition, King Boo appears as an enemy in several Ghost House courses.
• An image of King Boo could be found on the ground at the Spooky Trails in Mario + Rabbids Kingdom Battle.
• In Tetris 99, he made a cameo appearance during a Luigi's Mansion 3 promotional event.

Other Media

• In the Super Mario-Kun manga, King Boo appeared in a short chapter based on Luigi's Mansion. It was similar to his role in the game, including inhabiting a copy of Bowser, but he was sucked up much more quickly.
• King Boo made a cameo appearance attending Bowser's wedding in the 2023 CGI film The Super Mario Bros. Movie. The movie used his design from the Mario games, and he was the only Boo to appear in the film.

Trivia

• He is called Boss Teresa in the Japanese version (Teresa being the Japanese name for Boo).
• In Luigi's Mansion, he has 500 HP.
• In Luigi's Mansion 3, he introduces himself by declaring "It's-a me, King Boo!", a parody of Mario's introduction from Super Mario 64.