Jon winced as pain lanced through his skull and with a crack, two horns sprouted from his brow. His fingers and toes twisted into claws and with another crack, two bat like wings grew from his back. He hissed in pain and there was the sound of ripping as his pants tore open and a long tail forced it's way out. He panted heavily, exhausted and with each pant his pallid complexion darkened and became more ruddy until it reached the colour of dried blood. And with that it was over.
His family stared at him in shock.
"Cool," grinned his brother Mikey. His mother just fainted.