On a bright Saturday morning, Donkey Kong (DK) and Waluigi were playing 18 holes. While they were making their way to the tenth hole along the perimeter of Bowser's Castle, the two accidentally triggered a trap door that led them to Kamek's laboratory.

Inside is a cabinet of vials that range from fetid potions to saccharine mixtures; bookshelves filled with cookbooks, spell books, classic books, and old Nintendo Power magazines; games and accessories for various Nintendo consoles spanning from NES to Switch; Funko Pops of Nintendo, Disney, anime, and other characters; and framed photos of Bowser and his minions on their adventures. Rats on their lunch break scurried across the floor after glancing at the tennis master and primate duo.

Using his peripheral vision, Waluigi spotted an arsenal of wands on his left and thought of pawning one off for many coins. DK snatched one wand from the wall and began waving it around while he bounced. Waluigi saw it as an opportunity to try another wand for a quick test. As he made his way to the window, DK's vigorous instincts made him cast a fireball at a bookshelf. A lock of a black book took the damage while it fell to the stone floor. The two rushed over to pick up the book only to discover spells relating to many kinks (e.g., Tanooki suits, Boos, bondage with Yoshi's tongue). They flipped through the pages to find what kinks to implement—and combine—on unsuspecting candidates. DK and Waluigi have something different in mind, but they discover what kinks they share by pointing to select ones in unison. They darted out the window with glee to find whom to test their wands on. There were pairs of candidates DK and Waluigi ruled out:

Mario and Luigi (not good enough)

Peach and Daisy (too obvious)

Toad and Toadette (too creepy)

Hammer Bro and Nabbit (too resilient)

And then came Pauline and Rosalina—relaxing at a busy Blooper Bay to get some sun. Three nearby Lumas were assembling a battle scene: one was building a fortress while the other two were organizing the armies and artilleries. Rosalina was getting her tan up with her fancy reflector. When a Sidestepper pinched her left cheek, she yelped while cupping the crimson pinch marks with two hands. Pauline took notice of the problem before opening up a first aid kit to take out clean gauze and an ointment.

Behind the bushes, DK and Waluigi memorized the movements to cast a spell on the two unsuspecting ladies. They counted to three with their fingers before casting the magic with great aim. The two ladies felt their bodies numb while they watched their wrists lock together before two bracelets linked with the opposite pair.

"Rosalina, what is going on?!"

"I am not sure, Pauline! We are immobilized below our necks from the looks of it!" Rosalina replied.

Their breasts began to swell gradually as the two ladies gasped for air. While they stared at the expansion in horror with tears in their eyes, Rosalina's butt and hips began to expand outward. Pauline tilted her head to the right as far as she could.

"Rosalina, your backside—it's expanding too!"

"So is yours!" Rosalina loomed over her now-massive breasts to see Pauline's butt growing, although the latter's is not as large as the former's. Their leg muscles bulked to provide extra support for the heavyweight ladies.

The two ladies cried for help as their bikinis changed shape and color to accommodate the new measurements. The bottoms transform into null-bulge thongs that make the wearers feel like they are about to come but are always denied that opportunity. Pauline and Rosalina did not notice that under their heaving breasts, but they at least saw their bikinis' colors, glow-in-the-dark flames, and pinball decals become that of DK and Waluigi respectively.

Before they could get a chance to accuse the two of chauvinism and sexual assault, their minds began to cloud while they stared blankly at each other. Years of memories replaced with thoughts of servitude and masochism along with repeated mantras and familiar musical cues occupied the minds of the two swollen bimbos, although some leftover vocabulary remained inside. Their personalities were slightly modified to match that of DK and Waluigi.

Once the spell fully succeeded, Pauline and Rosalina regained control of their exaggerated bodies only to squirm with the bracelets imprisoning them and their assets rubbing and bumping together. Every attempt to orgasm was futile and more tears mixed with mascara flowed down the women's cheeks.

"Ugh! Pauline! My titties are, like, so huge!" Rosalina cried. Her cries began to sound more like Waluigi's iconic "WAH!".

"Ohmigawd! Stop bumping your cock against mine—we…can't…come!" Pauline grunted as she tried to release imaginary ejaculate to no avail.

"Oh! We are so WAH-bbly with our fat jugs, down to our fat, useless cocks 'n' balls, and around to our phat asses! That's "phat" with a "P-H," you know!"

Pauline's newly acquired primal instincts caused her to move with vigor. She took Rosalina with her across the beach as she made monkey noises. Their swollen assets jiggled and bounced in all directions and every bystander—including Mario and Luigi themselves—watched the two vapid airheads laugh and bounce in ecstasy. As for DK and Waluigi: they turned around to see an angry Kamek armed with a wand and revenge.