Complete Monster/Mario

> "*Yes, it was I who broke the Dark Moon! Not a difficult task when you have a power-enhancing jewel on your crown like this one. And now that all the ghosts of Evershade Valley are under my control, it's time for the rest of you to become my subjects too! You, that annoying scientist, and all your friends will look great hanging on the walls of my throne room! Aaaaaah ha ha ha!*"
> -King Boo revealing his plan in *Luigi's Mansion: Dark Moon*.
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While a very light-hearted, fun loving kind of series that is known for it's happy and cheery aesthetics, even Mario isn't immune to these guys showing up every now and then. Needless to say, Mario's not going to party or race with these folks.

* Mario & Luigi: Partners In Time*: The younger Princess Shroob is the acting ruler of the Shroobs, and debuts leading an invasion force to lay waste to the Mushroom Kingdom and depose Princess Peach. Under her heel, the Mushroom Kingdom is reduced to a charnel wasteland, while Toad towns and villages are depopulated so the Shroobs can suck out their lifeforce to fuel their spacecraft, an agonizing and wasting process for the captured Toads. She also unleashes the Yoshi-eating Yoob on the Mushroom Kingdom, transforming whatever it eats into more Yoobs. Princess Shroob also makes a vile public spectacle of Princess Peach's attempted execution, trying to feed her to Petey Piranha in front of a bloodthirsty audience of thousands. Princess Shroob is the crowning example of cruelty even among her Always Chaotic Evil species, and is one of the most sadistic villains ever to appear in a* Mario *game.*
	+ From the second game in the *Paper Mario* series there's the Shadow Queen, a savage demonic despot with a lust for power. She destroyed an entire city and murdered thousands who got in her way, and then destroyed town after town, having her minions steal treasures to put in her palace. She then created dungeons and torture chambers for people to be feasted on by her pet dragons, and also created the Crystal Stars to keep the world in this state. Why she did all this you ask? **No reason.** And even when she was defeated, she trapped the four heroes who defeated her into boxes for one thousand years showing that even defeat wouldn't prevent her savage cruelty. When Sir Grodus brings her back to life, she proves to be still as monstrous as she was a thousand years ago when the first thing she does upon possessing Peach's body is blasting Grodus to pieces, reducing him to nothing more than his head, just for thinking he could control her, and during her battle she even devours the entire audience to restore herself. What makes the latter especially gruesome is that you can hear them scream in pain as they are pulled down into the depths and absorbed by her malevolent form. A true demon seeking to crush the entire world under heel, the Shadow Queen stands as possibly the greatest evil Mario has ever encountered.
* The third game in the *Paper Mario* series gives us a rather vile example in Dimentio, a sadistic sociopath who puts the Monster in Monster Clown. While he's introduced by forcing a benevolent ancient guardian to fight Mario to the death, he mostly seems like a goofy, simile-obsessed minion of Count Bleck's aside from that one nasty moment when he uses his own comrade, O'Chunks, as a guinea pig for his floral sprout project. It isn't until near the end of the game however when his sociopathic nature becomes far more apparent, starting when he sends Mario, Peach, and Bowser to the Underworld after he did the same to his ally Mr. L (A brainwashed Luigi) while casually cracking jokes at their expense (Don't worry, they get better). And at the game's climax, Template:Spoiler As you can tell by now, he's pretty much the Nintendo equivalent to Kefka Palazzo.
* While King Boo tends to be someone willing to race or play sports with Mario and friends in spinoffs or shows up as a boss to fill in space in other games, it's the *Luigi's Mansion* games where we see the guy at his worst. He started off as a Well-Intentioned Extremist in the first game who was very fond of his Boos and went out of his way to rescue a powerful one named Boolossus from one of Professor E. Gadd's paintings... but after being defeated by Luigi, he completely and utterly casts away any and all redeeming qualities in the sequel. Thirsty for revenge against his hated enemy, King Boo shatters the Dark Moon of Evershade Valley and turns the peaceful spirits living there feral and nasty, enslaving them against their will. After sending them out to cause mayhem in the valley, he kidnaps Mario and a couple of Toads and imprisons them in paintings, while they're completely aware and unable to move. And in case if you thought that he still cared about his fellow ghosts, that's a big, resounding NOPE. King Boo performs all sorts of nasty experiments on his ghost minions and happily treats his Boos as disposable pawns, throwing them at Luigi with reckless abandon. Template:Spoiler In *Luigi's Mansion 3*, he is set free by Hellen Gravely, and together they gather Luigi and his friends in the Last Resort hotel in another attempt to trap them in paintings. When Hellen and her staff are all captured, King Boo dismisses them as worthless failures and eventually tries to absorb the entire hotel, including all the captured ghosts and his own Boos, into a group painting just to capture Luigi. Since most of the series' darker villains are relegated to the RPG's, it's almost shocking to see this sociopathic madman in one of the more mainstream titles where the villains tend to be Bowser and his goofy henchmen. It should be noted though that King Boo *only* counts as this in the *Luigi's Mansion* series, particularly since the second game: he doesn't qualify in any other games that feature appearances by him due to being willing to participate in parties and sports with Mario in some or being a generic villain in others. Thanks to Negative Continuity being in effect, he only meets this trope's

qualifications in the *Luigi's Mansion* series since *Dark Moon*.

* Mario + Rabbids:Rabbid Kingdom,Megabug is an an evil virus that became an threat to Mario and The Rabbits,, it attempted to erase everything in existence and was pretty much causing many horrible things to happen throughout the game. It also straight-up possessed Bowser toward the end of the game to presumably gain power. There is no denying that MegaBug is indeed one of the bigger threats in the Mario series.

* Mario + Rabbids Sparks of Hope:Cursa is a malevolent entity of darkness that was once but a mere fragment of MegaBug,it had somehow gained sentience, and sought to plunge the universe in darkness. Catching Rosalina by surprise as she and the Lumas greeted some wayward Rabbids, it had possessed her form, indirectly leading to the creation of the Sparks in the process. In order to suppress Rosalina's traits of heroism, it had absorbed the energy of the Sparks, Rabbid-Luma hybrids. To do so, it created an army of corrupted Rabbids and brainwashed Bowser's minions. Cursa soon created the four Spark Hunters: Bedrock, Midnite, Daphne, and Edge. However, Edge betrayed Cursa after gaining enough free will to see how evil it was, and has since vowed to save as many Sparks as she can. Sometime after the events of the previous game, Mario and his friends are enjoying a relaxing day on Princess Peach's Castle grounds, before a Spark abruptly falls from the sky. It turns out that he was fleeing from a gigantic manta ray, who proceeds to spread Darkmess, a type of dark matter, across the land and kidnaps Rabbid Peach. Mario and Beep-0 leap in to save her, before the two manage to hold off waves of enemies. Soon enough, Cursa arrives to confront them, but the heroes are rescued by their friends in their new ship, the WM ARC. Therefore it ordered the Spark Hunters to help round up the remaining Sparks, only for the heroes to defeat them too. Eventually, the crew manages to corner Cursa, who is briefly incapacitated when Rosalina shows herself, revealing that she has been kidnapped and absorbed by the creature. She is captured again, but not before giving the heroes a projection crystal and opening a portal to help them escape. Through the crystal, the heroes are able to learn the full story of Cursa’s past. Upon arrival at Cursa's stronghold, the heroes fight Darkmess versions of both Bowser and Edge. The group manages to thwart Cursa by destroying its arms, causing it to release every last Spark it consumed as well as Rosalina. After three rounds of helping the latter charge up her magic, the heroes finally defeat Cursa, saving the galaxy and ending Cursa’s reign of terror.

## Other Media

* *Super Mario: Goddess of the Demon World Empire*, by Ikkei Kawai: In this manga adaptation of the 1993 live-action film, President Koopa loses his few positive qualities while remaining the tyrannical ruler of Dinohattan. After ousting the rightful king, who he is implied to have turned into fungus, Koopa assembled an army by forcibly devolving his own subjects into brutish, subservient Goombas. Wanting to conquer the Earth as well by merging it with Dinohattan, Koopa orders his cousins, Iggy and Spike, to acquire the meteorite fragment that will allow him to do so, and when the two fail him, Koopa devolves them into Goombas while ignoring their pleas of Anything But That. Later, after Iggy and Spike accidentally kill themselves causing the dimensional merge, Koopa and his Goombas are shown happily blasting every human in sight with their Devo Guns, turning them into helpless monkeys, before Daisy undoes the merge and Koopa is killed by Mario.