The light blue sky loomed over the lands, with white clouds scattered around in just the right frequency as to contribute to the usual pretty picture of the Mushroom Kingdom, the centerpiece of which was the tall, light grey castle with red roof tiling. But you see, this kingdom's fair ruler was nowhere to be found. In an absolutely shocking turn of events not a single soul in the kingdom had seen coming, Princess Peach had been abducted, by none other than the reptilian rascal known as Bowser.
Hope, however, arose in the form of two heroes, one clad in red, the other in green, the latter a little taller and thinner than the former.
"C'mon! This way!" Mario urged his brother, heading in the direction Bowser's airship had taken the princess.
Unable to shake off a sense of déjà vu, Luigi followed him, hoping to find something that would make their job easier.
His prayers were answered in the form of two yellow cubes floating a few feet above the ground. "Great! One for us both!"
Mario wasted no time in hitting one of the blocks. Out came an orange and yellow flower. He touched it, and this caused his red hat and shirt to turn white, and his blue overalls to turn the same shade of red his hat and shirt usually were.
Optimistic for the contents of the remaining block, Luigi jumped up and bashed it. What came out wasn't any sort of magical outfit-changing trinket, but rather…
"Kamek!" he cried out in fright.
"Magikoopa!" his brother exclaimed at the same time.
"The red one is right!" the Magikoopa thundered at Luigi. "And for your mistake, you shall be punished!"
*sigh*... why did this have to be a Mario Maker level? Do people really think hitting a ? block and getting an enemy is fun? Regardless, it was Luigi that was then attacked by a Koopa wizard. It waved its wand and shot Luigi before flying away.
Luigi rubbed his eyes. As the light faded away, the world around him became gradually more clear, including Mario looking at him in surprise.
"What? What'sa matter?" Luigi paused for a moment and realized he felt… different. For one thing, his nose felt bigger. He touched it with his hand… which, when placed in front of him, turned out to be green, visible since his gloves were gone for some reason. One look in a nearby river depicted the reflection of a Yoshi, with skin the shade of green of Luigi's hat and shirt, his characteristic mustache on its nose, a saddle the color of his overalls, and brown shoes. His hat was the only item of clothing that had been retained.
Now, usually, it would be bad form to say, "And then Luigi did that scream from the Mama Luigi episode", but since this is a crackfic, I'll just do that anyhow.
"Hey! Hey! Cool it!" Mario urged him. "Maybe it's just-a new power-up?"
Then a Goomba walked over to him. When it made contact with him, it caused his fire powers to wear off and his outfit to return to normal.
To put that theory to the test, Luigi reached down and touched the Goomba. But no, he stayed the same. He groaned in defeat.
"Well, at least this doesn't mean we-a can't save the day!" Mario pointed out optimistically.
"...No. I-a guess not."
Luigi then yelped as Mario jumped onto him. "Onward!" Mario declared, pointing forward.
Luigi exhaled through his large nose for a considerable length of time before he trudged forward.
"So you see, Luig," Mario was assuring his brother. "There are much worse dinosaurs you could've ended up as."
As if on cue to demonstrate the bizarre point, a figure walked up behind them. It was Barney for some reason. "I love you, you love—"
Mario kicked Barney hard in the belly, sending him plummeting into an abyss. Thankfully, because he wasn't a video game character and couldn't use extra lives, it wasn't possible for Barney to come back after dying.
"Mario!" Luigi scolded. "You can't just go around murdering people for being annoying!"
"...It, eh, looked-a like one of Bowser's new hires. Speaking of which, you know the great thing about what just happened?" Mario asked.
"...What could possibly be great about this?"
"You can eat raw Goombas and Koopas! Usually you-a gotta cook 'em first, but Yoshis have different digestive systems. Why don't-a you try it?" Mario pointed at a nearby Koopa Troopa.
Luigi considered. He'd long since gotten over the moral compunctions he'd initially had about slaughtering masses of Bowser's armies, so eating one alive, as opposed to in the form of Koopa Soup, wasn't much of a stretch. Might as well take advantage of his situation. "O-akay." So he unfurled his tongue slowly to see how long it now was… the idea that it really was so incredibly long left a weird sort of feeling. Nonetheless, when it touched the Koopa, the minion yelped out in fear when the tongue stuck to him and pulled him into Luigi's mouth. Luigi didn't know about his natural Yoshi reflexes, and proceeded to swallow the Koopa whole. "...Not bad."
Luigi kept trying that as the journey continued, making sure to sample at least one of every enemy. Some were tastier than others, of course, but it seemed weird that he enjoyed any at all. He also couldn't resist the various vegetables planted in the ground, indicated by red leaves billowing in the wind.
Eventually, they encountered a Chargin' Chuck. Luigi stuck out his tongue… but it was simply repelled back into his mouth, at which point he remembered that Yoshis weren't capable of eating Chargin' Chucks.
"Mmm…" a sultry female voice said.
Mario and Luigi looked very confused. The minion before them was the only one who could have said that, and they had never imagined any members of this particular group of enemies would be female.
The Chargin' Chuck… no, Chargin' Chandra turned around, then lay down in a seductive pose. "Stick your tongue in me, daddy."
After a few moments of realization, Luigi ran away in fear while screaming.
"Whoa!" Mario exclaimed, holding onto his hat while keeping a grip on the Yoshi.
"She wants-ta touch me inappropriately!"
When the Chargin' Chandra was out of sight, Luigi stopped and caught his breath.
"Can'ta blame you," Mario admitted. "If someone tries ta touch you in a place or in a way that makes-a you feel uncomfortable, that'sa no good."
A few universes away, a certain hedgehog felt like his work had been plagiarized, but he didn't know why.
Mario reached into his overall pocket.
"Whatta you doing?" Luigi questioned.
"Gettin' us outta here and straight to Bowser," Mario answered, producing a Warp Whistle. "Not aboutta sit here and watch my bro get prepositioned by… those."
Luigi breathed a sigh of relief and gratitude, his annoyance with Mario's insistence on riding him fading. "Thanks…"
Mario played the tune, and they were both whisked away.
Gone were the lush plains and valleys, for the duo were now surrounded by lava, rock, and volcanoes. Directly in front of them was an enormous castle, made up of several towers of grey bricks, each tower with a green, pointy roof.
They approached the door, only to be stopped by a burlesque Koopa bouncer. "No Yoshis," he informed them, pointing to a sign.
"...So I can come in if I leave him outside?" Mario asked.
"Mhm."
"Why am I allowed in if-a Bowser doesn't want me to defeat him?"
"Look, I don't make the rules, okay? I wonder that myself, like why he orders the green Troopas to walk off ledges even when it means certain doom."
"It's been one of those days…" Mario complained. "C'mon, Luigi."
"Where are we going?"
When they were sufficiently far away and the bouncer wasn't looking, Mario pointed to the back of the castle. There were several Koopa Troopas with blue shells all stationed in front of the back door.
Realizing the plan, Luigi ate one right up, causing him to sprout wings at either side of his body. The remaining Troopas fled for their lives, but Mario caught one and took its shell. He flapped them and ascended upward until he was hovering in front of a window on the top floor. Mario threw a shell at the aforementioned window, shattering it for the two of them to enter through.
Having bypassed the majority of the castle via this speedrun trick, they finally arrived in Bowser's room. Portraits of the Koopa King were hung on the walls of the large hideout, and the only illumination was provided by bubbling lava.
After the brothers finished the run through the hallway to the bridge, Bowser finally revealed himself by jumping down from somewhere up before finally landing onto the bridge with an audible THUNK! noise.
"What the—how'd you bring that in here?!" he demanded, seeing Mario riding the forbidden dinosaur. "I specifically told—wait." He took note of the hat the Yoshi was wearing, not to mention its facial hair, most uncharacteristic for the species. He put two and two together, then burst out laughing. "This… this is too good! Which one of my Magikoopas did this? He's getting a promotion! It's killing me!"
"Show him our secret weapon, Luigi!" Mario directed.
Incensed at the mockery, Luigi bent over and stretched his tongue out as far as it would go. It crossed the entire bridge, going underneath Bowser's legs before finally hitting the axe at the other side, causing the bridge to crumble away.
The laws of gravity didn't immediately kick in, but then Bowser looked down at the lava beneath him. "...Wait, that's illegal," he said, before finally plummeting.
The plumbers weren't particularly concerned. They'd seen this exact scenario enough times to know Bowser would inexplicably be alive and well shortly thereafter. Why couldn't he be more like Wart and leave them alone after being defeated once?
But now, the time had come for celebration. "Yay for you, Luigi!" Mario congratulated his brother, and high-fived him accordingly. "Now, how about gettin' us across?"
Luigi gulped. "You promise notta jump offa me midway?"
Mario seemed confused. "Why would I do that?"
"...No reason. Just makin-a sure." Luigi put the blue shell back in his mouth, causing his wings to re-sprout. He flew over the bridge with Mario in tow so they could go and free Peach.
One credits sequence of returning to the castle later…
Luigi rummaged through the shelves of the castle library. The feast he and Mario had enjoyed with the princess not long ago following their return had been bountiful, indeed containing spaghetti, and lotsa it, but now he was focused on finding a cure to his condition.
Out of the corner of his eye, he saw the princess standing in the wide doorway, so he turned his attention to her. "Ah, Princess! Fancy-a seein' you here."
"Fancy seeing you," she returned. "Like this… pardon the abrupt change of subject matter, but do you know what French kissing is, Luigi?"
"When you-a make out in France?"
"That's… not wrong. But I was referring to when two people interlock their tongues."
"Like a fusilli?"
"I suppose, yes. The appearance of the two aforementioned tongues intertwined could be said to resemble a strand of fusilli pasta. And I'm sure you're also aware that Yoshis have very long tongues. I've always wondered what it would be like to engage in French kissing with one, but that would be bestiality. Usually, anyway. But I suppose in your case, technically, it doesn't count."
Luigi's tail started to wag behind him as he put the pieces together.
"What I'm saying is… perhaps you could humor me?"
Now that was an offer he couldn't refuse. For one thing, she was royalty. She could easily have him beheaded for not complying. Secondly, she was royalty. Any day where you get a saucy makeout session with a member of the royal family is a win.
"...Yeah. Yeah, I could do that!" Luigi descended from the ladder and slowly stuck out his tongue more and more.
Peach took ahold of it and gently coiled it around her own tongue as much as she could. Given the length difference, it wasn't that easy, but how good it felt more than justified the effort.
Peach wiggled her tongue around in the grasp of Luigi's, feeling between the gaps of the spring-esque shape the latter's had taken on. Luigi took this as a cue to loosen his grip, so he did. That wasn't what Peach had had in mind, but it would do, being a little less restrictive for both of them; she could move her tongue around and Luigi's didn't feel too tight, and Luigi could explore the inside of her mouth with more freedom. They soon became lost in each other's tongues, and ended up on the floor, with Luigi laying on top of Peach, securing her in a place of bliss.
Eventually, Peach coughed. Luigi immediately removed his tongue. "Princess!" he exclaimed. "Are you okay?"
Peach gently put her hand to her throat. "You kind of just put your tongue down my throat."
"Oh. I'mma so sorry…"
"But I didn't say 'stop'."
So Luigi went back to covering her open mouth with his, and inserting his tongue, slowly but surely sending it further down her throat where it had been before.
After several minutes, they stopped, and sat on the carpeted floor. "You're an excellent kisser," Peach complimented him. She saw that Luigi's hat had fallen off during their tryst, so she put it back on for him. "You're-a Luigi. Number one."
A/N: And that's my celebration of MAR10! If you're wondering why Peach and Luigi would do that blursed French kissing session at the end when Mario could walk in at any moment, remember that there's no hard and fast evidence that Mario and Peach are canonically a couple. Consider how she rejects both him and Bowser at the end of Odyssey. Also consider how she gives both him and Luigi a kiss on the cheek at the end of Hotel Mario. Maybe the three of them have some sort of poly thing going on (not the kind where Mario and Luigi are romantically in love with each other because that would be plain cursed, nothing blursed about it). And before you say, "Hotel Mario was NOT canon!", remember that the series has no canon. We know the Zelda CD-I games are non-canon because they did not appear in the official timeline, but no such thing has happened for Mario, so I am free to assume it is canon.