Super Mario Bros.

Toad is set alight by his fellow Goombas, which is enough of a distraction to allow Iggy and Spike to break free of their grasp. Daisy puts out Toad's fire but can't stick around before the Goombas give chase, so the Koopa cousins lead her away, explaining that they are forever in her debt. They were actually underlings of her father before he was overthrown, and they set about showing her the hideous pile of fungus he is now, the result of being the first victim of Koopa's de-evolution. They slink outside to give her some time alone.

Meanwhile, Mario and Luigi continue exploring, only to stumble upon a hideously long drop, a shaft coated in fungus. There's no other exits besides the way they came, and Luigi, ever the daredevil, decides to be the one brave enough to progress forward. Oh, no, he's not gonna jump is he?

OH NOOOOO

...?

He's flying! Oh man, Luigi was right. You can do anything with a little faith.
 

Of course, this was just a prank on Luigi's part, he's just dangling from a hook (how? why?), but he's already convinced Mario enough for him to take the plunge, only to legitimately fall to his death. Thankfully, a bed of fungus spawns beneath him and springs him back into the air, allowing Luigi to grab hold of him. Of course, only now do they see another exit, so they start swinging on over there.

Back in the king's chamber, Yoshi makes his way in and alerts Daisy to a laser gun holstered on a pillar, which despite its unfriendly design, is actually just a simple laser pointer for accessing a computer terminal, granting Daisy access to the camera system and a loudspeaker.

Daisy uses this to inform the brothers where she's located, but unknown to her, Koopa is also eavesdropping on it and knows what she's up to. The two make their way into a pipe where Luigi takes note of a mushroom in the fungus, noticing that it's actually moving of its own accord, possibly in an attempt to communicate, though despite Mario's further claims that he's crazy, we get the gist by now. Koopa is informed that his troops are ready to be deployed to our dimension, but he didn't expect them to be ready so soon; apparently Lena had made commands under his name, and since she's got the meteorite, he orders her to be arrested.
 

Mario and Luigi make their way into the king's chamber and reunite with Daisy, and are given an awkward introduction to her father. Mario's pretty grossed out, but Luigi thinks it's a great honour and is happy to know that despite being a hideous ball of unpleasant vegetation, the king is helping them in their quest to topple Koopa. Daisy asks Mario how Daniella is ("Daniella! I promised to take her to Wrestlemania!") and informed that she's been kidnapped as well, so he darts over to that floor. However, Koopa and a horde of Goombas march into the corridor as Luigi and Daisy try to leave, kidnapping them as Koopa sets his invasion into motion.

Lena tries to make her way to the gateway discreetly, but is ambushed by Koopa's troops and arrested. The meteorite is returned to Koopa, much to his delight, he sets his Goombas into motion - with Luigi and Daisy forced to watch, he will begin the invasion of the alternate dimension!

Mario sneaks into the holding cell for the kidnapped women, attempting to silently crawl over the grate ceiling and sneak them out, but one of them loudly says hello to him, prompting the Goomba to open fire, though a swift kick to the chest takes him down. He then opens up the vent as the girls take the Goomba's mattress, and he plans a rather ridiculous escape plan...

Wheeeeeeee!!

The Goombas aren't settling for that, no sir, so they chase after on their own mattress. Rather stupidly, they don't actually use their flamethrowers or any means of actually stopping the escapees besides just crashing into them, so they're all easily disposed of - one is knocked off by a dangling stalactite, while the rest are flipped over by Mario dunking a wrench into a grate. They approach the exit...
 

And through the magic of cheap blue-screen, they fly out of the tunnel and straight into Koopa, knocking over him and several of his Goombas. The happy reunion is cut short, as Koopa's armed himself with a de-evolution gun, but he spends too much time blabbing and not enough time zapping, as Mario takes hold of a spare Stomper and sends it jetting towards him, knocking him over a railing and into a giant bucket.
 

Koopa's not letting that stop him, and thanks to the fact the bucket is now miraculously dangled in the air, he can open fire on the lot of them, though he hits nothing but explosive billboards. Mario is given Luigi's belt and told to "trust the fungus," so he swings over to the bucket and kicks Koopa in the head, causing him to drop the meteorite fragment...

Which lands back in Lena's grasp, though in the process she falls over a railing (I could make a crack about the health and safety regulations, but come on, the city's a shithole) and lands on a power generator, zapping her something fierce, though she doesn't seem fazed by it. Koopa thinks he's just dropped the fragment in the bucket, digging his way through the grit in an attempt to find it, though Mario dangles one of his shoelaces in his fist and teases Koopa into thinking he's the one who has the fragment necklace.

Lena dashes off to the gateway to do what she always dreamed of doing, while Luigi, Daisy and the girls give chase. In the cave where the brothers originally found themselves, Lena tries to force the fragment into the meteorite embedded in the floor; the girls are sent through the portal to warn everyone of the Goomba invasion while Luigi and Daisy stay behind to try and stop the madwoman.

Mario drops to the street below and makes his way onto an overpass, Koopa following suit. While attempting to intimidate the lizard king with something from Luigi's belt, he pulls out the small clockwork device he found in the police station, prompting everyone to run away screaming. A Bob-Omb!

He winds it.

He sets it down.

It's on the move.

... well, crap.

The Bob-Omb falls down a long chute of fungus, but is still on the move at the very bottom.

Lena forces the fragment into the meteorite after some difficulty, revelling in the power she feels through the merger, but the energy is too much and she is blasted against the wall, nothing more than an embedded skeleton. "She really makes an impression, huh?" Luigi comments. This is no laughing matter, however - Daisy finally understands, only she is capable of handling the fragment, and she's got to take it out before the worlds fully merge!

Koopa mocks Mario's attempt to defeat him while Mario goads him into just blasting him. However, Koopa's gun conks out and Mario's hand starts drifting away like sand in the wind. The villainous reptile smiles - he didn't have the meteorite! Their worlds are now merging, and there's nothing he can do about it!

Luigi and Daisy attempt to take the fragment out, but it's wedged well in - simple hand power isn't sufficient, and the drill just ricochets around the walls. They start using the wheel puller, which seems to be doing the trick...

Back in Brooklyn, the World Trade Centres dissolve into decayed states - the way they looked like in Koopa's dimension! Mario, Koopa and his Goombas fade into the construction site, where the university students and Scapelli and his crew are still located. Koopa's gun is totally fried, so he takes a Goomba's de-evolution gun and blasts it at Mario, who quickly leaps out of the way...

... resulting in Scapelli taking the shot. The unfriendly businessman de-evolves into a chimpanzee, prompting everyone to laugh at the silly little primate and his crew to be in mere disbelief about the situation. Koopa takes another shot at Mario, who whips out the mushroom from Luigi's belt, it swelling up to shield him from the blast and acting as a sufficient projectile to knock the gun from Koopa's hands.

Daisy and Luigi finally wedge the fragment out of the meteorite, causing Mario, Koopa and his crew to warp back to the scummy dimension. The younger brother and the princess make their way back onto an overpass, bumping into Toad along the way who equips them with de-evolution guns, and even Bertha makes a reappearance to throw Luigi a new pair of Stompers!

Toad distracts the Goombas by playing on his harmonica, causing them to dance and get knocked down by a flustered Koopa, while Luigi leaps onto Mario's platform, equips him with a de-evolution gun and the two open fire on the fiendish fiend. Meanwhile, the Bob-Omb has still been going, passing over the street, climbing up a wall and now ending up underneath the overpass, right beneath Koopa's feet, when...

Koopa flies high into the air and comes down again like a pile of bricks, landing into the bucket once more. Things are eerily quiet, however - there's no sound or motion coming from inside the bucket. Surely Koopa isn't...?

OH GAAAAHD

Koopa has mutated into some kind of hideous reptilian reptile! Who would've expected this? Mario fires off a snappy quote ("See ya later, alligator!") (did you notice how I said snappy? oh ho ho ho) and they open fire on the beast with the de-evolution guns once more. Two long, concentrated blasts are enough to finish it off, the creature warping and contorting...

... as it spills out of the bucket, mutating from scaly creature into hideous slop along the way, and splashing into a fine mess upon the street.

Without hesitation, the bystanders erupt into glorious applause, and revelling in the moment, Mario holds onto his brother as he leaps through the air offering a sign of peace. The Goombas dance merrily in the streets, and heck, through completely unexplained means, the king mutates back to his usual self! His first desire isn't to see his daughter again, or try and set things right, or even simply comment on how nice it is to be human again. He just says, "love those plumbers." There's a man with priorities.

Mario, Luigi and Daisy return to the cave, anxious to return to their own dimension. Luigi is all too happy to get back and start mackin' some love with the princess, but Daisy remains where she is. She's aware of how much Luigi cares for her, but she wouldn't want to leave until she can know her father and help in getting her world back into shape once more after Koopa's tyrannical rule. Luigi understands, and the two share a passionate kiss before the gateway is opened, as she, Yoshi and Toad see them off.

Brooklyn, three weeks later. Mario and Daniella are cooking up a spicy dinner while Luigi is moping around, watching Miraculous World. His mood soars when the new topic is mentioned: "They courageously crossed a dimensional bridge,and managed to return the missing Brooklyn girls, and save a parallel world from a ruthless dictator. I would call them the Super Mario Brothers." Awwwww yeah.

However, they receive a surprise visit.

It's Daisy! Armed with a gun and sporting a kickass appearance, she needs their help. She refuses to elaborate, merely gasping "you're never going to believe this..." Mario has no qualms, that's enough to get him preparing for adventure. He's a believer now.

The cartridges for the Stomper boots are styled after Bullet Bills. Cute.

Likewise, the de-evolution gun is just a repainted Super Scope. People say the computer interface pistol look like a NES Zapper, but really, it's just a generic sci-fi gun.

Wait, what happened to Iggy and Spike?

"I must say, we have a very excited proposal."
"A video game, based on your many adventures."
"What would you call it?"
 

"Iggy's World."
"The Indomitable Spike."
"... The Super Koopa Cousins!"