I was in a dingy Mississippi Delta bar last year and I overheard this old black bluesman whispering about a "Howlin' Harp" northerner who got his moniker of "Mudboy Slim" by selling his "vote" to the RATs, in return for incomparable musical ability.
The RAT he sold his "vote" to was named "Slick" and he gave him the Slim handle.
Kinda like the story of some 'ol bluesman whose name I can't recall.