He couldn't stop his right hand again as it fondled his cock still sticking out of his fly. His hand looked so strange and demonic but he couldn't understand why. As he felt himself become aroused again his hand ran up and down his dick. This time he felt even harder if that was even possible. He started jerking off again feeling his cock start to morph. Each stroke his thumb would rub his glans almost trying to flatten his uncut head. He also noticed veins starting to pop out on his member, flush with blood making his cock look faintly purple. As the demonic hand quickend its pace the head of his cock flattened out making a point. As the cleft left the tip of his cock it also started to gain length after every stroke, his modest 5in shaft growing to a foot in length. The purple color shifted to a deep red, flowing from the top to the bottom as a sheath started to form at the base of his dick.
Every stroke brought Sam more and more pleasure but it also brought more changes to the rest of his body. Slowly his face started to transform, eyebrows bowing out, and cheeks growing into a demonic face. He felt his other hand begin to contort as he brought it up to his face and watched with a mix of fear and pleasure changing to match the other. The white pigment from his hands began to flow up his arms and worked its way across his whole body. As his face turned white, blue and red makeup appeared around his eyes and mouth making him look the part of a demonic class clown.
At this point his cock was ready for release. Sam felt his dick spasm again and watched as he blew his load all over his lap. The first few loads where pearly white but as it continued it turned into yellowish feral cum ready to morph who ever came into contact into Sam’s fuck toy.
“As you can see every joke you make will give me more control over your body.” The voice in his head said. “Before long you’ll be my slave.”
“No,” Sam said out loud. “I’m not going to let you do this!
“Oh but you have no choice, you signed away your soul to me when you got that stamp on your hand,” the voice replied, “you may try to resist but in the end you’ll give in.”
“Oh god,” Sam thought as he surveyed himself. The teenager now looked like a demonic clown with a massive red rocket of a cock. He tried to button himself back up but his new package was causing him difficulty as his new sheath oriented his dick upwards towards his taut stomach. He felt horny and hungry for some reason, these changes had changed more than his body. Sam raised his head from where he was sitting in the stall as he heard the door to the bathroom open.