Hellsongs are a 3-piece Scandinavian band who play traditional heavy metal songs in the style of early 70's folk music. Their versions of these songs are not parodies of the originals, nor are they note-for-note replications; the band instead finds totally new ways of arranging and presenting the original material. Their transformation of Metallica's dirge-thrash number 'Blackened' into a sprightly, almost Joni Mitchell-esque singalong is bordering on genius, while their interpretation of Iron Maiden's chest-beating power anthem 'Run to The Hills' as a deeply introspective slice of acoustic melancholia is equally charming.

Is this a new genre? Or have other artists pioneered this great idea?