Here I used Hero Forge to create the muscular young man and the woman who has undergone a (not entirely voluntary) transformation. The man can't believe what he sees.

Story
Ava's body began to change. First, her teeth turned into fangs, her nails became claws, and fur of a brownish color grew on her body. Her muscles began to swell and cat-like paws burst out of her sandals. Her clothes ripped until she was only wearing her underwear. Matthew was completely rigid and had his mouth open. Ava had transformed before his eyes into an athletic, muscular anthropomorphic lioness. She was like a werewolf, only in lion form. Ava was deeply ashamed that she had transformed in front of Matthew. She spoke to him and he responded. Matthew couldn't believe what he had witnessed. On the one hand he wanted to run away and hope he wouldn't become their prey, but on the other hand he was curious. After he collected himself, he wanted answers from Ava. Ava explained to Matthew that she is a werelion and it runs in her family. The transformation is most often activated by fear, anger and even excitement. Ava said she was sorry he found out the way he did, she didn't want to reveal herself until he knew her long enough. She told Matthew that if he doesn't accept her and wants to stay away from her, then so be it. But she asked him not to tell anyone. With sadness in her voice, she told him that she liked him and had hoped to try with him, but if fate didn't want it that way.