The King!
"It is not your castle" Mario declared while a very pale Luigi shivered behind him.
"Is that so? Well I'm bigger than you and I say it is!"
"Oh what great logic; I guess we're defeated."
Bowser smirked and said "Sarcasm doesn't become you plumber. Maybe you're just trying to act all big and tough even though you know you don't stand a chance."
"There's always a chance as long as people are willing to stand up to a bully!"
"Ha! You're nothing but a nuisance and you do know what bullies do to nuisances, right?"
With that Bowser, leapt from landing above and crashed down mere feet from the brothers. He was huge; easily taller than the height-gifted Luigi. Both brothers backed up but Mario's determined expression slipped only for a moment. Bowser roared, blowing the plumbers hats off and causing Luigi to shriek in fear. The Koopa King laughed and swiped at the bros with his massive claws. The bros dove out of the way and Bowser laughed again.
"Oh this is going to be fun. Certainly not much of a challenge but it will be very entertaining."
He lunged at the quivering Luigi who scuttled out of harm's way like a clumsy crab. Luigi screamed as Bowser opened his mouth and released a large fire ball. Luigi acted like a rolling pin so as to avoid being flambéed. Bowser turned for another attempt but felt a fireball strike him on the side of the head. He then turned his attention to Mario who was pulsing with Fireflower energy with index finger extended.
"You're not the only one with firepower, Bowser."
"You call that firepower" the Koopa King roared with laughter "That's like attacking a volcano with a candle!"
He roared and Mario found himself dodging fireballs almost as large as himself. Mario began to run in a wide circle while Bowser turned on the spot, still trying to fry him. Mario ran part of the way up the grand staircase while Bowser adjusted his aim accordingly. Mario then ran down the stairs and pelted Bowser's belly with his own fire balls. While the large Koopa was reacting to this, Mario whipped a large wrench from his pocket and brought it down on one of Bowser's feet.
"Ouch! That hurt!"
"Oh I'm so sorry" Mario replied sarcastically
Bowser opened his mouth wide and this time released a steady stream of fire. Mario froze for a moment and his wrench was engulfed in the flames. It grew red hot in seconds and the plumber dropped it pain. Bowser unleashed a final fireball on the fallen tool and reduced it to a molten puddle.
"Now what cha going to do, plumber?"
Mario answered by shooting a fireball into Bowser's eye. The Koopa King clasped a hand to his face and wailed in pain.
"You little pest!"
"Thank you for the compliment."
Bowser dropped his hand and prepared to roast Mario when another wrench hit him in the back of the head. He froze in pain as a lump began to form and Mario took the moment to put some distance between him and the large koopa. Bowser turned to see Luigi with his hand still raised from having hurled the tool. He was shaking but stood his ground as pulled a hammer from his pocket. Bowser took several long steps and quickly approached the plumber who responded by wildly running forward and smashing Bowser on the nose with the hammer.
"Ow! You're going to regret…ow!"
Mario was busy pelting Bowser's slowly blackening tail with fireballs. Bowser leaped into the air and landed hard right next to Mario. The plumber was rocked by the impact and then flung painfully across the room due a swipe from Bowser's claw. Mario smashed into a wall and his firey glow faded away. He noticed this and vainly tried to launch a fireball. Bowser simply laughed.
"Ha! I guess that's the end of the super powers."
"I wouldn't bet on it" Luigi said from behind Bowser as Mario began to smile
"Finally remembered that Super Mushroom in your pocket I see" Mario commented
Bowser turned around and his eyes grew wide to see the giant Luigi towering over him. "Well that's just cheating."
"I don't think you're in a position to comment on cheating" Luigi replied
"Hey, I stole this place fair and square!"
"Then this is fair and square" Luigi said as he jumped as high as he safely could and stomped the floor. Bowser was jolted and Luigi took the opportunity to kick him. The Koopa King doubled over in pain and fought to catch his breath. It was Luigi's turn to laugh but his glee turned into shrieks as Bowser set his boot on fire. Luigi stomped around trying to put out the boot and Bowser was dancing around to avoid the large foot.
"Get away from me you overgrown plumber!"
"How about one that is simply pleasingly plump?" Mario said as he stomped hard on Bowser's tail
Bowser turned on the spot and grabbed Mario by the throat. "I don't know; let's have a look at you fatty." He squeezed a bit and Mario gasped in pain "Doesn't seem like a good model."
"Put him down!" Luigi raged
"What are you going to do about it? If you do anything at all, he's done for!" Luigi glared at Bowser but passively put his hands at his sides. Bowser laughed and loosened his grip just a little. Mario twisted for a better position and bit Bowser's finger. Bowser howled in pain and tried to shake Mario loose but the plumber just bit harder. Finally the plumber was flung across the room and Bowser examined his injured finger. Luigi released his anger in an almighty kick that actually knocked Bowser over.
"What is with you two? Why won't you just loose?"
"Why would I lose when I'm this big?" Luigi asked
Bowser responded with a series of huge fireballs and Luigi screamed as they struck him. His super powered body withstood the flames fairly well but the damage was sufficient to break the mushroom's spell.
"If size matters" Bowser said standing back up "then I suppose the tables just turned."
"What's that?" Mario asked "You want a table?"
Bowser turned in time to be smashed in the face by a side table Mario had found against a wall. The already beat up Koopa King staggered a bit and was unprepared for what happened next.
"Together?" Mario said with a glance at Luigi
"Sure thing!"
They took a running start and simultaneously kicked Bowser right in the stomach. This seemed to be too much for the koopa and he was engulfed in a cloud of smoke. The Mario Bros watched in astonishment as the smoke cleared and they saw not Bowser but a Goomba.
"Dang it! I'm going to be in so much trouble" the battered Goomba exclaimed
"What?" Luigi stammered "What?"
"Where's Bowser?" Mario asked
"Not here idiot" the Goomba answered
"I don't get it" Luigi said
"Obviously"
"Who are you and what's going on?" Mario demanded to know
"I'll talk; just don't beat me up anymore. I'm Goomrex, leader of the Goomba's in King Bowser's army. He wanted someone here to cement his power in the Mushroom Kingdom and keep people in fear while he continued his work elsewhere."
"Well that's…clever" Luigi said
"Wait a minute…" Mario suddenly looked worried "Peach!"
He ran up the stairs and down the hall to the Princess' room. He burst through the door and found the room to be empty. He called for her and looked all over but she wasn't in there. He ran back to the door and slammed right into Toad.
"Oof…Mario!"
"Hey Toad"
"Is it over? Did you beat that Bowser guy up?"
"Well it wasn't really him but yeah."
"I thought so! The spells on this place seem to be breaking. I could actually leave my room."
"That's great. Do you know where they were keeping Peach?"
"Oh Mario" Toad said as his face fell "I'm terribly sorry but our Princess is in another castle."