King Boo, otherwise now known as Princess Booette.
Luigi had just recently, secretly, shamelessly bought a Super Crown from his princessified nemesis. Doubling that was the fact that that nemesis of his was tasked with aiding his other nemesis Bowser with spreading the crowns.
But hey. No one was around, so it's not like he'd be in trouble.
"Boy, these-a crowns sure are weird," Luigi muttered.
"Oh, don't mind it, lil' Luigi," Princess Booette said. "Just put the darn thing on and get goin' already."
"A-alright, sure..."
The green plumber gulped. He slowly lowered the crown towards his head.
Slowly...
...slowly...
...slowly...
...and slo-
"Gee, can ya be any more nervous!?" Booette exclaimed and floated up to him, grabbing his crown. "Put it on!" She then smashed it onto his head.
Luigi felt his body changing, and suddenly everything shined in both their visions.
...and then a boring poof of smoke.
When the brightness died down, Booette found herself staring at an adorable brunette with a green hat and... well, you know. It's just a girl cosplaying as Luigi, speaking by appearances. And somehow she... whoa, nice knockers, Booette thought.
"...u-um, please stop-a staring," Luigiette said.
That darn Italian accent is sorta cute on her too...! Booette looked around. Then she smirked at her nemesis. "Hey. Hey, Luigi... what say you keep your Super Crown on and... we get to know each other better?"
Luigiette's jaw dropped.
"...well? I think we can drop all our bad chemistry and get along if we stay like this..."
"...yeah... no thanks, good-a-bye!"
Suddenly, the princessified plumber quickly turned around and ran away through the dark, eerie hallway.
Booette frowned. "Darn. And here I thought she'd be a perfect wife... oh well. Give chase!" she ordered herself and began floating after him.
"Oh, geez!" Luigiette screamed. "This isn't the result I wanted!" she said, then jumped as she passed another ghost who was halfway protruding through the ground. "I-a already have a girlfriend!"
"Come on, Luigi!" Booette called. "Don't you think having a ghost girlfriend is way cooler? Also I'm going to call you Lui from now on!"
Luigiette shook her head, not slowing down at all. "I prefer-a living ones!"
"Damn, that's a shame." Booette charged power within her hands, as a minion Boo gathered in front of her. She grabbed the Boo and aimed at Luigi. "Boo Edition Hadouken!"
"What?" Luigiette turned her head around slightly and saw a Boo being propelled towards her at an incredible speed. "Aawawawa!" She quickly ducked, stopping in her tracks as the Boo flew over his head. This meant he stopped running, of course.
"Aha! Gotcha!" Booette exclaimed, grabbing his shoulder.
Or at least she tried.
Her hands went through Luigiette's shoulder.
"...ah," they both voiced. Then Luigiette smiled- it was a very small smile. "That's-a that then." She then took the easy way out and jumped through the window, landing safely as they were both on the first floor anyways.
Booette watched as Luigiette quickly scurried out of the area. "Drats."
She looked at her hands.
"...why couldn't I touch her now?" she mused. "This crown sure does weird stuff to me."
Then, suddenly, she got an idea that stemmed from nowhere.
"Princess Daisy! Princess Daisy!" a Toad exclaimed. "Princess Daisy! Princess Da-"
"What!?" Daisy herself shouted as she kicked the door to her chambers opened, the Toad jumping back. "Gee, can't a girl get a more gentle awakening!?"
"N-never mind that!" the Toad said.
Wow, rude, she thought.
"Y-you've got a visitor outside!"
Daisy raised an eyebrow. "Ugh. Visitors. I'll go dress myself and go outside soon, tell them that..."
"Pft, no need!" a new voice interrupted. The two looked around. Suddenly, Princess Booette's head popped through the wall between them. "I'm already here anyways!"
"HOLY WHAT THE FRIGGIN' CRAP!" Daisy screamed. As Toad let out a... uh... high-pitched scream, she grabbed the Toad and threw it at Booette's face, which quickly sank back into the wall before she got hit. "What was that!?"
"It is I, King Boo!" Booette said again, this time reappearing behind her. "Or... uh... Queen Boo now. Or apparently, as Bowser told me the Internet went by, Princess Booette."
Hearing of this, the princess of Sarasaland rolled her eyes before glaring at the ghost. "And what does Luigi's nemesis wants from me?" she asked, with hostility.
"Oh, nothing. Just thought I should try doing what Bowser does."
"...?" Before Daisy could ask more questions, several Boos flew into the room. "What the-"
"Get her!" Booette exclaimed.
Oh, Daisy thought. It's another stupid kidnap-the-princess scheme... she realized.