There's nothing metal about John Travolta and Olivia Newton John singing "You're the One That I Want." BUT if you distort those vocals and add in a few down-tuned guitars, what you get is a death metal anthem that shows just how bad and evil of a girl Sandy really was by the end of Grease. 

Girl's got some darkness in her.

Source: andyrehfeldt

I'm fairly confident by the end of that song Sandy devoured Danny's soul.