Reads like the setup of a short story. In the final act the horseshoe would be physically important, either to help the protagonist¹ and make their point or hurt them² and disprove the claim.
¹ E.g. it contains an inscription which provides a vital clue.
I like the 2nd ending, but when they're taken to the hospital for horseshoe-induced head trauma, an early-stage brain tumor is discovered & operated on, thus ultimately saving their life.
¹ E.g. it contains an inscription which provides a vital clue.
² E.g. it falls on their head.