On his Gris-Gris album. According to the liner notes there was a mid 19th century root doctor in New Orleans by the (real) name of John Montaigne, operating both as a pimp and a voodoo priest under the Bayou John or Dr. John moniker. One of his partners in crime was a Pauline Rebennack. One of Mac's ancestors?
Johnny Jenkins [featuring slide work by Duane Allman]
Beck [elements of Johnny Jenkins' version in Loser]
Oasis [same Johnny Jenkins elements as Beck's version in Go Let It Out]
North Mississippi All Stars [in Down In Mississippi featuring Widespread Panic organist JoJo Hermann]