Jon tried to keep his mind blank, but keeping his mind blank reminded him of that scene at the end of Ghostbusters, where Zuul says that their next thought will determine how they're destroyed and...
Jon felt a strong cramp in his stomach. He bent over and grabbed his middle, and found it giving way a lot more easily than it should. The cramp spread quickly, and by the time Jon straightened himself back up, his gut was bulging his shirt out, but where it stuck out it was white. Karyn saw the color as it spread up Jon's neck and down his arms. Jon's thighs flared out, ripping his jeans, followed by his calves, and his head became stout and wide. A sailor's cap dropped from thin air onto his head as most of his facial features disappeared, and he let out a roar. His entire body popped outwards, ripping off all of his clothes and leaving him completely naked aside from a blue sailor's collar that had mysteriously appeared.
Jon had become the Stay Puft Marshmallow Man.
