On our way home from the mounds, we stopped in Tupelo and ate at Johnnie’s Drive-In (908 E. Main). It’s pretty famous as Elvis’ favorite place for hamburgers. Elvis’ house is not even 1/2 mile from Johnnie’s:
Johnnie’s is an old-style drive in where the servers walk out to your car as soon as they see you pull up – there’s no order board or button to push, or anything.
They serve two kinds of hamburgers – all-meat hamburgers, and doughburgers (meat and dough (flour/water)). We got doughburgers:
Corinth has slugburgers, Tupelo has doughburgers, and they exist in Cullman (Busy Bee), Decatur (C.F. Penn), and Moulton (NeSmith Hamburgers) too. 
If you’re really into slugburgers, there’s the annual slugburger festival in Corinth, July 10-12 this year…