"Probably just high-res metadata," she muttered, rubbing her tired eyes.

This is a story about the night "Psycho" became more than just a song on a playlist for a girl named Elara—it became the soundtrack to a digital haunting.

She never did find a way to delete the file. Now, whenever she walks into a room with a speaker, the opening notes of "Psycho" begin to play softly, a reminder that some "free" downloads come with a price you can't pay in cash.