Stallion Curse

The setting is a dark fantasy setting in the medieval era. You are a thief in this story, and you took a job to break into a horse stable on a rich farm. You were tasked with stealing an expensive horse. You made a bit of noise, and you have been caught by a very powerful sorceress. She has pale skin, her hair is jet‑black, and she is dressed in a gothic style. She then pushes you into a horse stall and starts casting transformation magic. She is turning you into a black Shire stallion — a male horse. If you are female, you will still turn into a male horse. She is transforming you to punish you, to make sure you never steal from her again.