"Heh, he's gonna blow a gasket when he sees this!" Boruto chirped, despite being a fox, as he eagerly reached for the door handle, but just as his claws tapped against the metal, he wasn't ready for his hand to suddenly double in size, and this time it hurt!
"Ow! What the fuck!" Boruto yelled, clutching his hand close as he stumbled back a bit, holding his trembling hand up, the sound of his bones cracking audible to his sensitive ears as his fingers involuntarily curled slightly, his claws popping out as they increased in size, their shape absolutely lethal. He grunted, feeling his ears lengthen as well, his face cracking as his muzzle pulled out more as well, pupils completely dilated from the experience, his sharpening canines digging into his blackening lip, drawing a bit of blood.
"Agh! It hurts!" He groaned, his arm feeling like someone was pulling on it with a horse, falling to the ground, his arm easily doubling in size, his elbow now a bit beyond his sleeve. It looked a bit noodly, his muscle stretched tight around the lengthened appendage, but within seconds, the tissue burned, Boruto moaning as his forearms swelled, the growth pushing on towards his bicep, the growing muscle ripping his sleeve apart.
He looked almost comical, his arm twice the length it should be, but he didn't have to wait long, groaning as his other arm followed suit, falling to the ground, grunting as his legs adjusted their stance slightly, making it easier for him to remain on all fours.
"Wh-what's happening?" Boruto asked, almost a little bit scared as he tried to figure out some way, any way to stop this, the rest of his body catching up, growing pecs ripping his shirt open to reveal his budding 6-pack, his thighs ripping his pants apart as well, leaving him in just a tight pair of pants more resembling short shorts than anything else.
Arching forward as his back cracked, his vertebra pushing up against his skin, Boruto looked down, noticing his blonde fur beginning to take on a burnt orangish hue. "L-like the Ky-agghghg Grrrrrrr" He gasped, reaching up as he found he lost his voice, only able to make growling sounds. Finally, the worst pain hit him in his spine, Boruto doubling over as not one, but two, but eight more tails burst out from his spine, curling around his legs, rubbing against the wall, even teasing his bulge.
Speaking of his bulge, he moaned as he felt himself strangely grow hard despite the pain, his cock pushing up against the strained material, drawing it tight around his growing ass. Within seconds, the material gave way, Boruto moaning as it slapped against his furred chest, slowly sliding up against his stomach. Unable to resist, he reached one clawed hand down, gradually giving it a stroke, even as it surged bigger, Boruto looking down with now purplish eyes as the tip grew more pointed, the base growing more knotted as his furred balls began pushing his hindlegs apart.
He moaned, his furred paw stroking along his growing cock, already starting to push alongside his pecs, as his back pushed up against the ceiling, his arms and legs against the walls, his 9 tails trying to do everything they could to break down the wall, but inside, Boruto was freaking out, if he broke out, looking like he did now, he could trigger a Kyuubi panic, like what happened when his dad was born... but... he looked down at his massive hulking body... Maybe it could be worth it... thoughts of crushing buildings under his massive frame. He shook his head. "Grrrrrrrrr" He growled, unable to make words. 'Okay Boruto, keep calm, keep in control...' He thought frantically, even as the room cracked around, his instincts screaming at him to let loose...