Witnesses told police Timothy Wilks and a friend had approached a group of people outside a family trampoline park in Nashville, holding large knives.
Mr Wilks was then shot by a 23-year-old, who told police he had had no idea it had been a "prank" and had been acting in self-defence.
Mr Wilks's friend told officers the "prank" had been for a YouTube video.
No-one has been arrested over the death.
