Mario dimension:
Mario collects all 120 power stars and runs up the infinite stairs and goes down the pipe at the end of the hall. Mario looks up and past a massive group of obstacles, he sees the exit pipe a few hundred feet away up in the sky. He looks down and shakes his head and thinks keep it together, just one more level then I rescue Peach...and hopefully for the last time, mamamia...
After a brutal 15 minutes of running, jumping, climbing and dodging several obstacles, Mario makes it to the top and says get ready Bowser! He jumps in. Mario lands on a wide platform hovering way above a lava pit and comes face to face with Bowser. Bowser laughs and Mario says I wouldn't be laughing if I were you! Bowser says you want Peach back? Well you'll have to beat me first. Bowser spits out a huge fire blast at Mario and Mario double back flips over the blast to avoid it. Bowser charges at Mario and Mario runs at him and just before Bowser goes to head butt him, Mario front flips over Bowser but Bowser looks behind him and slashes at Mario with his tail. Mario gets 3 small cuts in his side and flew back but landed on his feet. Bowser says, you're finished! Mario has a grin on his face and says oh yeah? Mario reaches into his pocket and pulls out a small green box, he throws it into the air and it inflates then Mario jumps into the green block and a metal cap came out and Mario grabs it then puts it on. Mario turned into Metal Mario then charges at Bowser. Bowser has a concerned look on his face, and goes to punch Metal Mario and hits him in the face but hurts his wrist and yells out in pain. Metal Mario punches Bowser in the gut a few times and he stumbles back then Metal Mario jumps in the air and double drop kicks him in the face and sends him flying into a giant mine on the outskirts of the platform and he smashes into it and it explodes and Bowser flew off in the other direction and landed right in front of Metal Mario. Metal Mario looks down at Bowser passed out and looks up then sees Princess Peach hovering down towards him. All of a sudden, Bowser grunts and stands up then a black and red aura surround him and he grows another couple feet and gets more buff and his teeth and hair grew a bit longer and he had black eyes with red pupils. Metal Mario runs at Bowser and Bowser swings his tail and hits Metal Mario in the face and Mario fell and landed on his back. Bowser runs up and starts stomping on him, trying to crush him. Mario grabs his foot with both hands and manages to push Bowser off of him. Mario struggles to get up then punches Bowser in the face a couple times then Bowser slashes through Metal Mario and cuts right through the metal and into his flesh. Mario yells out in pain. Bowser head butts Metal Mario and puts a dent in his head and sends him flying. Bowser charges up a flamethrower then fires at Mario and he slowly melts away into nothing. Bowser lets out a long evil laugh. I have finally killed Mario! bwa ha ha ha!
Meanwhile on the roof top of the castle, Yoshi stood there waiting for Mario to finish off Bowser. He started to worry because he didn't think it would take so long then all of a sudden, the front door of the castle gets kicked out by Bowser and he walks out into the field with all his minions following him. He has Peach attached to a chain forcing her to follow him wherever he went. He tells his entire crew that Mario has finally been killed and it's time to find Yoshi and Luigi and kill them too. Yoshi looks sad when he hears the news so he jumps in behind the castle and runs off to go find Luigi.
2 Hours later:
Bowser had become way more powerful and held Peach captive. Peach cried as she grieved for Mario and Bowser laughs then pins her down and comes face to face with her. His eyes glowed black and red and he speaks in a deeper more raspy voice than before. Mario is finished and I'm going after Yoshi and Luigi next. You will be by my side for the rest of your life! She softly asks in a scared voice, what are you going to do with me? Bowser pauses then smirks, you'll found out soon enough...
Yoshi arrives back in town and knocks on the door of a house. The door opens and Luigi stands at the door. Yoshi tells Luigi about Mario's fate and how they plan to go after the two of them as well. Luigi is in disbelief, he asks Yoshi how its possible because Mario has triumphed over Bowser 3 times (mario bros 1, mario bros 3 and super mario world) but failed a 4th time. He tells Yoshi he wont be apart of it, he said hes done fighting and that's why he didn't help Mario on this adventure. Yoshi gets angry and cant believe Luigi wont help him beat Bowser so Yoshi slams the door and goes after Bowser himself.