According to this video’s uploader, his brother decided he’d had about enough of the noise from a marching band outside his house. Grabbing his old, out-of-tune trumpet, he decided he’d mess with them a bit.
As the marchers begin their piece, the prankster cuts in with his crummy-sounding notes, causing the brass section of the band to examine their instruments, wearing puzzled expressions. Soon enough, they realize that the rogue trumpet is not being played by a band member, and they look up to find their foe. The band isn’t too amused, but we got a great laugh out of this prank.