I have had JAX beer in New Orleans that I swear was made from Mississippi river water and it was the ONLY beer I have ever had that I could NOT finish. Mississippi mud sounds ominous but I'm game.
I've had Mississippi Mud in the bottle (well, it was more like a jug) and I didn't find it to be anything special in terms of taste. As I recall, it was sort of a mild stout, but it came in a jug with no widget, so there was no head on it.
The name didn't faze me. I once lost a bet and had to drink a bottle of fleabath runoff called "Old Scratch":