Step-by-step explanation:
He could feel the sweat beading against his forehead as his heart began to beat faster. His body tensed as an immense amount of pain ripped through it. His face contorted in agony, extending out in front of him to form a muzzle, he fell forward onto his hands. His screams turned into a bark as dark fur sprouted up across his body like freshly planted sod. His bones elongated and changed their shape as the clothes he once wore shed from him. He hunched down, shaking his mane, his newly pointed teeth poked out from his mouth.