His body began to ripple with changes and didn't seem to notice them much. At first it was localized in his face. His cheeks puffed up, then his chin expanded into something twice it's size. His neck thickened as the changes then spread everywhere else.
His stomach stretched outward pushing against the booth he was sitting in, his butt growing fatter and wider, lifting him up. All his clothes began to split as his growth was too much for them. Even his shoes felt tight, so he kicked them off, leaving his socks to take the damnage of his swelling feet.
He picked up his burger with thick chubby fingers and began to eat it, not even remotly aware of anything being different.
"Now then, it's time to give him some real fun..."