Disclaimer: I do not own anything and this is considerably non-canon to the main story. Enjoy.
BGM: Mein Kleiner Gruner Kaktus (Comedian Harmonists)
"Argh! Lost to the blasted plumbers again!" Bowser growled. He crawled out from the lava and sat on his throne. "How can I win if I can't kidnap the brothers or the princess!"
"Why not kidnap both?" Cinder said as she appeared before Bowser.
"You are a genius," Bowser said. "But who are you? And where did you come from?"
"Would you like to read this Gaiden Chapter to know how we got here?" She asked, holding Chapter 39 before moving on. "Also these creatures you see here are called Grimm. They are monsters that are attracted to bad emotions and feast on negativity."
"So basically Heartle-" Bowser was about to summarize before Cinder stopped him.
"Grimm," she corrected him.
"But why not Heartless," Bowser asked.
"We do not want to get a copyright strike," Cinder quickly explained. "Anyways, I can help you kidnap both the Princess and the plumbers. You can trust me."
"Okay, I believe you," Bowser said.
Meanwhile…
"Ouchie Ouch!" Mario shouted as he was swatted away by a Beowulf when he tried to punch it. "I surrender!"
"Finally, with the brothers defeated and the princess kidnapped, who is gonna stop me!" Bowser shouted as he and his forces flew back to the Koopa Kingdom with the Mario Bros. and Princess Peach captured.
Elsewhere…
"Jeez, it sure is boring around here." Ruby Rose said while she laid on her bed.
"I sure hope nothing strange happens." Weiss prayed.
*Audience Laughing*
"Hey girls, wanna go on a fun adventure?" Headmaster Ozpin asked.
"Sure," Ruby responded.
"You have to go save a princess and her saviors from an evil turtle." Ozpin explained their mission.
"Neat."
"In a kingdom filled with mushrooms," the headmaster also added.
"We're going to get high," Yang said as Team RWBY left for the Mushroom Kingdom.
"This is going to be a fun adventure. What can go wrong?" Ruby asked with an innocent smile.
Everything paused before Future Ruby began to speak. "Little that I know, that what I said, would greatly mess up my life forever."
World 1…
"What the hell is this?" Weiss shouted as she saw the floating ? blocks, mushrooms with eyes, and Goombas walking with angry faces on them.
"This is a crossover fanfiction, nothing here makes sense," Toadsworth spoke to them.
"Okay, we believe you," Team R_BY said, except Weiss who was still believing that logic can solve everything.
"Anyways, I need your help saving the princess and the Mario Brothers from Bowser."
"Seems easy," Yang confidently said.
"Who is seven Worlds away," Toadsworth added.
"There it is," Blake said.
"But before you leave, would you like to purchase this game to know-" Toadsworth lifted up a Super Mario Bros. DS game but only to find that Team RWBY was already gone. "Hopefully the girl in white doesn't feel disappointed."
At World 1-Castle…
Stop BGM
BGM: TMNT Theme Song (Teenage Mutant Ninja Turtles 2003)
*Record Scratches*
Resuming BGM: Mein Kleiner Gruner Kaktus (Comedian Harmonists)
BOOOM
"Ouchie Ouch!" The Koopa Bros cried in pain as they were launched back by Yang's punch.
"Don't do that, it will give us a copyright strike." Blake said to them.
"No, you girls copied us first!" Green argued.
"No we didn't," Weiss shouted back.
"Yes, you did!"
"No we didn't!"
"Yes, you did!"
"Well you're trash and forgettable!" Yang interrupted The Koopa Bros and Weiss as she launched the former again into a wall.
"Ouchie Ouch!"
"I'm sorry, but the Princess and the Brothers are in another castle," A Toad told them.
Bowser's Castle…
"Team RWBY has passed the Koopa Bros and are coming here, what should we do?" General Guy asked Bowser who was dancing.
"Absolutely nothing," he answered.
World 2…
"I don't like sand, it's rough, coarse, and it gets everywhere." Blake panted as the desert heat was starting to get to her.
"Hello, welcome to the desert that everyone can't goddamn name." Mr. E said before giving them Boomerang Flowers and water. "Take this, so you girls don't die."
"Sweet," Ruby smiled.
World 2-Castle…
"I'm sorry, but the Princess and the Brothers are in another castle," another Toad told them.
'Suddenly this adventure doesn't seem fun anymore,' Weiss thought.
World 3…
"And now we're at the beach," Ruby said as she and her team were now wearing swimsuits. "I wonder how Zwei is doing?"
Back at Beacon…
"Zwei, where are you?" Jaune shouted for the missing corgi while looking under a bench.
"What an idiot poopface…" Cardin mocked him as he walked by.
"Pancakes! (I want to break his legs!)," Nora spoke with hidden anger.
"Can I join?" Pyrrha asked.
Back with RWBY…
"That was sure fun!" Yang smiled as they changed back to their original outfits and walked towards the forest.
"Skipping over how we were almost eaten by a giant eel and chased by a giant bone shark, doesn't count as fun." Weiss quietly countered.
Without them noticing, General Guy stood on top of his Airship as a few Shy Guys armed the King Bill Blaster. "Fire in the HOLE!"
BOOOOOOOM
"Now let's go make sure they're dead and go see that underwater castle that would definitely not resurrect some kind of ancient evil." General Guy ordered his men.
World 4…
"What the-" Ruby woke up to see herself in a treehouse. "Where am I?"
"(Hey you, you're finally awake!)"
Immediately she was met face-to-face with the owner of the treehouse himself, Donkey Kong.
"Oh my god!" Ruby panicked as she jumped back.
Donkey Kong used his own language as he spoke to Ruby. "(Hello there! My name is Donkey Kong, and I'm the one who brought you here.)"
"Do you know where my friends are?"
"(Yes, I know where they are. But before that-)" Donkey Kong then held onto a collection of Donkey Kong Games. "(-would you like to play these games to know my story?)"
One Level and Gaming Session Later…
"Hello there," Kamek appeared before Ruby, Blake, Diddy Kong, and Donkey Kong. "My name is Kamek and I am here to kill you!" He then summoned Naval Piranha from the lake as it roared and breathed fire. "Behold, a killer fire-breathing plant with the most obvious weak-spot!"
"Totally not scary at all!" Ruby said as she dodged an attack. Then, after delivering the final blow, the Naval Piranha sank below the waters. "We did it."
"But where are Weiss and Yang?" Blake asked.
Meanwhile…
"Hey Crocodile, I'm going to beat you up so hard you'll get a mental breakdown just by looking at me!" Yang smirked at King K. Rool.
"Bring it on you blonde bimbo!" King K. Rool roared as the two of them began to fight in a boxing ring.
"Why am I the only smart one- Ouchie Ouch!" Weiss complained before she got attacked by a Kritter.
As soon as she launched King K. Rool out from his castle, she smiled. "And that's how you hit it off with a Yang!"
Meanwhile…
"GOD DAMMIT, BARB!"
Back with RWBY…
"Did anyone hear that?" Ruby asked.
"Must have been the wind," Blake said.
Back in World 3…
"I'm back baby!" Dry Bowser stepped on the beach. "And I'm going to be everyone's problem!"
World 5…
Stop BGM
BGM: Let it Go (Frozen)
Team RWBY trudged through the heavy snow as the blizzard stormed on. Weiss stood in front of them as she began to sing.
However…
*Record Scratch*
"Ouchie Ouch!"
BGM: Mein Kleiner Gruner Kaktus (Comedian Harmonists)
Weiss was hit by a snowball from one of the Mr. Blizzards. One of them held up a sign saying, "No copyright! Especially from Disney!"
"Hi there, I'm Popo and this is my sister Nana," One of the Ice Climbers said. "Let's go climb a mountain together."
"Okay, sure!" Ruby agreed.
Few Minutes Later…
"Worst," Ruby panted with her team at the top of the summit.
"Woo," Blake began to catch her breath.
"Mistake."
"Woo," Yang panted.
"Ever."
"Woo," Weiss heavily breathed.
"Hey losers and rejects!" Kamek appeared as Blizzaurus approached behind him. "Behold, an ice dragon that is definitely not an idiotic fairy!"
One Boss Fight Later…
"Wow, what an idiot," Yang commented at the disappearing Blizzaurus.
"Let's go slide down this mountain together!" Nana said.
"Sure!" Ruby enthusiastically complied.
"WEEEEEEEEE!" Everyone cheered as they slid down the mountain. Well, almost everyone.
"Ouchie Ouch!" Weiss cried out as she crashed into a tree.
World 5-Castle…
"Do you know what Ice King means?" Crystal King shouted at them.
"Yeah, a big nerd!" Yang shouted as she punched him.
"Hey there!" Roman Torchwick appeared with Neo by his side. "Let's fight."
Suddenly, a Super Bell fell on top of him, giving the criminal an orange cat suit.
Roman, now with a deadpan stare, looked at himself through the icy reflection on the floor. "Kill me…"
World 6…
"Hello there," Lucario appeared before them. "My name is Lucario, I am here to tell you that there are more worlds than this one."
"Where are you from?" Blake asked.
"Would you like to play these games to know my origins?" Lucario manifested Pokémon Diamond, Pearl, and Platinum out of nowhere. "Discounting the remake of the first two."
One Long Gaming Session Later…
"Come inside please," A sign in front of a Haunted House said. "It is definitely not a trap."
"Okay, we believe you." Team RWBY said as they entered the Haunted House.
"This is definitely a trap" Lucario shook his head before wandering in.
A Few Minutes Later…
"That was fun!" Ruby smiled as she held a plate of cookies and a note that said "It's just a prank, bro" on it.
World 6 Castle…
"Ah, ze RWBY and Lucario, prepare to die!" A Monty Mole spoke with a German Accent as he dove into his tank.
However, he was completely defeated as Weiss, with a newfound Cloud Flower Power-up, used it to destroy the tank with the Monty Mole inside it.
The tank exploded and sent the Monty Mole flying in the air.
"I'm blasting off!" Monty Mole cried until he became a twinkling star.
"I must leave, I need to do an errand." Lucario said to them before taking off.
"Let's go!" Blake shouted before they fell into a cannon.
The cannon then fires, sending Team RWBY into the sky.
"We're blasting off again!" Team RWBY cried.
World 7…
"How are we not dead? How are we standing on solid clouds?" Weiss asked as she felt like she just lost her mind.
"Like Toadsworth said, this is a crossover fanfiction. Nothing here makes sense." Blake said.
"Poyo!" A certain pink puffball entered the scene.
"Aw, you're so cute!" Ruby hugged Kirby.
"Poyo!" Kirby said as he held out Kirby games with a note saying, "Would you like to play these games to know about me."
One Gaming Session Later…
Stop BGM
BGM: Vordt of Boreal Valley (Dark Souls III) (1:45)
"Why do I hear Boss Music?" Kamek nervously asked as he saw Team RWBY stepped in.
"Poyo!" Kirby greeted him.
"AAAAAAAAAAAAAAAAHHHHHHHHHHHHH!" Kamek screamed.
Stop BGM
Resuming BGM: Mein Kleiner Gruner Kaktus (Comedian Harmonists)
"Ooh, Rainbow Road!" Ruby beamed at the race course.
"Let's go destroy our friendship!" Yang smiled as she revved up the engine of the Flame Rider.
The group proceed to do the following: Weiss was pushed off the ledge before getting pulled back by Lakitu, Ruby getting outrunned by Yang with a Golden Mushroom, Blake getting hit by a Blue Shell sent by Weiss, and Kirby being officially the winner of the race by speeding past Yang.
World 8…
"What the-" Weiss was shocked as she saw the Koopa Kingdom surrounded by active volcanoes.
"Looks like we're in Hell." Yang commented on the landscape.
"So what's the plan?" Blake asked.
"Rush in?"
"Good idea!" Ruby agreed.
"That's right, we're gonna battle in Hell!" General Guy said as his armada appeared. He was sitting on his tank, looking down at Team RWBY. "I got my Hell tank with me and you girls are not gonna pass!"
"Give us the rest of your sin points!" Yang shouted.
'Why is this becoming Shadow the Hedgehog Fandub?' Blake questioned herself.
"I'm blasting off again!" General Guy shouted when Yang destroyed his tank and launched him into the sky.
Within the volcano, Team RWBY then meets face-to-face with Dry Bowser.
"Hello there," Dry Bowser greeted them.
"Who the flipping flip are you?" Yang asked.
"I am King Bowser I. Remember me because I'll be one of your greatest adversaries in the upcoming adventures you'll have."
Eventually, Team RWBY managed to defeat him by tossing him into the lava below and resumed strolling towards Bowser's Castle. Unknown to them, Dry Bowser had survived as he swam to the lava bank and walked out.
"Hopefully, they'll remember me," he said, looking up before disappearing.
"I wonder who that was," Blake asked her teammates.
"What's his name again?" Yang had forgotten about it.
"No idea," Ruby shook her head.
World 8-Bowser's Castle...
"Hello losers, prepare to-" Kamek appeared before getting beaten up by Team RWBY. "Ouchie Ouch!" He cried as he was sent into a wall.
"Hello girls!" Bowser greeted them with a menacing grin. "Prepare to die! But first-" He then pulls out a Nintendo Switch. "-would you like to purchase this Nintendo Switch to find the best-"
"I prefer the Playstation 5 instead." Yang quickly denied.
"So you have chosen… DEATH!" Bowser roared as he attacked Yang, which resulted with strands of her hair falling off.
"Oh no!" Ruby panicked as she, Weiss, and Blake took a few steps back.
"No…" Yang's eyes turned red and her hair flared.
"Oops…!" Bowser realized his mistake and turned pale.
"YOU!" Yang angrily shouted and landed her punch on Bowser, which sent him flying out from his castle and into the lava.
"Hello, my name is Princess Peach and these are the Mario Brothers." Peach introduced herself and the Plumbers.
'My life is entirely a lie now…' Weiss mentally thought in her head while having a breakdown.
"Is she okay?" Luigi couldn't help but be worried about Weiss.
"Yeah, she's fine." Blake reassured him, ignoring her teammate's scream.
*Godzilla Screech sfx*
Everyone stopped to take a look outside and saw Bowser now in his giant state.
"Let's go big and do a Kaiju battle against Bowser!" Mario said, holding a Mega Mushroom.
"We did it," Ruby shouted as they finally defeated Bowser. "We beat Bowser."
"Let's use this conveniently placed Warp Pipe to take us back home." Princess Peach smiled as everyone took the green pipe back to the Mushroom Kingdom.
"Why didn't we use this in the first place?!" Weiss yelled as she entered.
Back with Bowser, he was now greeted by Cinder, who was joined with Emerald, Mercury, Neo, Roman, and his son, Junior.
"What the-" Bowser looked up to see them.
"Allow us to introduce ourselves," Cinder said. "My name is Cinder Fall, and these are my lacke- I mean, friends. This is Emerald Sustrai."
"Hi there."
"Mercury Black."
"I'm a jerk."
"And Roman Torchwick and Neo Politan. You'll find yourself having something in common with these two."
"I don't wanna be here," Roman said.
"I'm the best girl of all the RWBY franchise" Neo held up a sign.
"And Junior, why are you here?" Bowser turned towards his son.
"Plot relevance," Junior answered.
"Makes perfect sense."
"Anyways, let's go rebuild your castle and take revenge." Cinder said.
"Sure." Bowser chuckled darkly.
At Beacon...
As Team RWBY, Mario, Luigi, and Peach returned to the Mushroom Kingdom, they immediately went to Beacon to see what was going on.
"Welcome back, Team RWBY," Ozpin greeted them. "Congratulations on your mission and many things have happened since you're gone."
"Pancakes! (We have a pet Boo!)" Nora smiled as she showed it to everyone.
"Boo? JNPR?" Yang thought for a moment before a smile crept up to her face.
"Oh… no…" RWB_ and everyone else paled at the realization.
"Booniper!"
"GOD DAMMIT/PANCAKES!" Everyone shouted at once.
"So where's the other team?" Peach asked Ozpin.
"You have to wait five stories for them to unite," the Headmaster said. "Also one of them has a split personality disorder that I totally have under control. You can trust me."
"Okay, I believe you."
At Smash Mansion…
"Medusa has returned and I need help." Palutena said as Pit came close to her.
"What about Team RWBY?" Lucario suggested.
"You are a genius," Palutena said. "I shall use my Divine Power of Persuasion to have them join my side."
In the RWBY Dorm Room…
"Hey girls! Wanna go on an adventure?" Palutena's voice spoke to them as a Heavenly Door appeared in front of their room. "I need your help saving the world and I promise it will be fun. You can trust me."
"Okay, we believe you," R_BY said.
"Ah shit, here we go again!" Weiss said.
"Hold up! I thought this was talking about your trauma." A voice interrupted the scene.
In Present Time…
Ruby Rose was now laying down on a red sofa while Cloud was sitting on a red velvet chair. Surprisingly, Cloud was her therapist as the two of them had something in common with each other.
"Yeah, but I wanna start off where I first began my adventure in a nutshell." Ruby explained. "Plus, this is an April Fools special. Nothing here is canon."
"Yeah, that is basically almost all fanfiction." Cloud said. "But like I was saying earlier, how is this related to your trauma?"
"Well, that was basically the calm before the storm. So let me tell you the story of how I obtained my PTSDRD. Also known as my Post-Traumatic Stress Dark Ruby Disorder."
Cloud lifted up his pen.
"In the next chapter! Probably. Maybe. Whenever the author decides to make another. I'm not even sure myself."
"God Damn it!"
To Be Determined… I Think... Probably... Maybe...
"Who the hell wrote this?"