Drawn by the excellent  NezumiChan

Carl didn't notice anything different until he reached the new song. Then blaring lyrics, thick, pounding beats and rumbling bass filled his ears, causing his nose to wrinkle. "Ugh, rap." He groaned, pressing his hands to his ears. However, something about it held his finger. It was rap, but not like any other rap he'd ever experienced. There was something...uniquely primal about it.

He kept his hands to his ears, not even noticing as his body began to shift, stomach pudging out , pushing up and tearing his shirt. In fact, his whole body was thickening, threatening to rip apart his clothing. His feet were expanding so fast that his shoes couldn't handle it, bursting into scraps.

Even his skin was changing as he listened, rapt with attention to the intense music, becoming slicker and developing dark patches. His pants were being destroyed from the back, not only by his swelling ass, but also by an emerging fluked tail. His face was broadening and rounding out into a slick muzzle.