Mario tugged his hat free of the horns now sprouting from his head, trying to spare it any further damage. As soon as his hat was off, he could see his hair beginning to lighten in shade - the very tips beginning to turn a familiar shade of red...
The plumber didn't need more than a few seconds to realize this had to be Bowser's doing. The strange mushroom, on top of these changes, pointed directly to the Koopa King. Mario raised a hand to his now-scaly forehead, bemoaning his gullibility. When he removed his hand, he could already see his hand beginning to thicken up; his fingernails lengthening and sharpening to points. Already bearing a somewhat stocky build, Mario was only growing broader as the changes continued unabated. He began to worry about stopping it - but, if he couldn't do that, he was sure that he could fix it.
He departed his bathroom and made his way into his living room, where a simple rotary phone sat on a shelf. Clumsily working his new claws into the dial, he decided to go right to the source - challenging Bowser for answers. It wasn't often that he had the opportunity to do so - after all, the Koopa was usually busy raising havoc or invading some kingdom or another - but... Well, he needed some way of inviting him to kart races.
As soon as he heard Bowser's rumbling voice on the other line, Mario's suspicions were confirmed. "Hello?" Bowser mused; a smug, knowing tone to his voice. "And who might this be?"
"It's-a--" Mario began; but he stopped himself. He huffed - and he could see a bit of smoke escape his new snout. "You know who it is!"
"Gwahaha! Of course I do. What's wrong, Mario? Is something the matter?"
"What did you do to me?" the plumber challenges; the phone in one hand, and the other holding his stomach. He could feel a heat building inside of him, and his overalls tightening as his body continues to broaden.
"I'll tell ya what I'm doin' - I'm turnin' the biggest pain in my royal rear into somethin' useful, for a change!" Bowser asserts. "Don't that sound good?"
There was a small part of Mario that was compelled to agree, but the plumber forcefully blurted out "No!" - stifling that part of himself for now. "What's it gonna take to turn me back?"
Bowser grumbled - while he clearly knew what was happening, it didn't seem to be going as well as he expected. "Well, maybe I have a way to do that." he groans. "But I ain't gonna let this chance slip. You're gonna do me a solid, plumber - and if you do a good job, and if you even want to go back to being a boring, old goody-two-shoes... Then maybe your king can be convinced to arrange something."
King - the word resounded in Mario's head; making his head feel hazy and knees feel weak. Gritting his new, sharper teeth, Mario muses "Then what do you want?"
Bowser chuckles darkly. "Well..."