The extraordinary English blues singer and guitar player Jo Ann Kelly used to sing "Death have Mercy" accapella around the clubs in the UK as part of her performance. The way she delivered it was chilling. For me at any rate, and I heard her do it on several occasions, it was one of those musical experiences where time stands still. It would silence a room full of rowdy drinkers and make the hair stand up on your neck. Spellbinding.