If you're a male mountain lion, this is the sweetest sound in the world: a female mountain lion calling for a mate.
If you're not a male mountain lion - well, we'll let you be the judge. The video below shows a female mountain lion in heat, and the sound is borderline unearthly. While it has its own sort of beauty, it could also easily be mistaken for a terrified human's screams. Or a ghost.
Listen below - but make sure to turn your volume down.