Packed into that set of “Who’s Gonna Save My Soul” demos and alternate takes is this unreleased Gnarls tune “Mystery Man.” It’s a b-side collage stitched of a couple sketches — Cee-Lo soulfully straining to a fat keyboard-and-backbeat vamp, bookended by a pair of Danger Mouse control-room geek-out instrumentals — so while it’s not Gnarls in fully realized pop mode, we do wind up with an interesting listen at the the pair letting loose and finding ways to save even their rougher ideas from the cutting room floor.

The Who’s Gonna Save My Soul EP is out 11/11 via Atlantic. It’ll include “Mystery Man,” four versions of the title track, and a live take on “Neighbors” from the 40 Watt Club. You can still head to gnarlsbarkley.com right now and download MP3s of all those “Soul” versions (the vid, too). After 11/11 it’ll all be gone.