A cover version of a cover version. When song C is clearly an uninspired version of song B which may or may not be an unspired version of song A.
In some people's book, a sin.
A: "Dude, your playlist is entirely made up of lame ass cover-covers of that old Tears for Fears song. Are you trying for emo kid of the year or what?"
B: "What are you talking about?!? Donnie Darko is awesome!"