Luffy was happily lapping up the spilled powder, not noticing as his body slowly started to grow larger! It was a gradual process. His legs slowly stretched longer, his hands spreading out more and more on the ground where they were planted while his feet pushed up against the straps of his sandals. He didn't even notice as his tongue was suddenly able to lap up more and more of the powder at one time, further fueling his impressive growth. His body retained the same proportions as he expanded; quite simply, more of him just kept coming into existence! The powder was fueling some sort of process in his body sending his normal growth patterns completely askew, kicking it into overdrive!
Finally, after the last of the powder was resting in Luffy's belly, he stood up, happily licking his lips, getting any last remnants of the powder from off his face and into his mouth. "Wow! That stuff tasted really good!" He patted his stomach only to notice something odd. "Hey...when did my clothes get so small?"
The buttons on his vest were being stretched to their max, small ovals of flesh visible between them as Luffy's body continued to bulge and expand within them. His shorts were no better off, riding halfway up his thighs, the cuffs pulled tight against them. All of this served to highlight Luffy's rather sizable bulge which was only growing larger along with the rest of him! He wiggled his thick toes as they grew over the edge of his sandals, the straps snapping one by one.
"Woah...I'm getting bigger!" Luffy said, his eyes wide as he looked over his body.
Suddenly, one by one, the buttons on his vest popped, flying into the dark recesses of the warehouse as they could no longer take the strain of Luffy's growth. A low tearing sound filled the air as his shorts followed suit, rips appearing all over the denim. To make matters worse, the waistband was starting to cut deep into his skin, making him wince. His large hands fumbled with the button before it mercifully popped off, the zipper running down until his bulge surged out passed it, his boxers clinging desperately to his hips, trying to survive the onslaught. As the shorts finally fell to pieces around him, leaving him only in his boxers, Luffy's head hit the roof of the warehouse, pressing stubbornly against it. "A-Aw man! I need to get out of here!"
He made his way over to the entrance only to trip over a small box, sending his massive body crashing to the ground. His vest tore clean in half as he got to his knees, his bent back ripping through it like wet tissue paper. Luffy crawled over to the entrance and was dismayed to see it was now far too small for him to leave through. He flicked the doors open with his fingers and put his hands through, trying to rip the door open wider. Unfortunately, it was impossible. The metal comprising the warehouse was far too thick! Even his gigantic size was no match for it.
"Crap! I'm stuck!" He muttered furiously to himself.
He sat back down, looking nervously up at the ceiling which was coming ever closer. At this rate he was going to get stuck in here! He moved to the back of the warehouse and hoped against hope he would just stop growing soon!