Sling Blade was the movie to make fun of in the late 90s. Comedians imitated Karl's voice, people dressed as Karl for Halloween, and a lot of people just called Karl "Sling Blade," as if that were his name. For example, "What are you going to be for Halloween?" "I am going to be Sling Blade, mmhmm."
References to and parodies of Sling Blade live on today. One creator on YouTube goes through fast-food drive thrus and places orders in his best Sling Blade voice, for example. And one memorable 30 Rock clip imagines "Sling Blade and Oprah on a Date."
Twenty years later, even as Billy Bob Thornton is finishing up Bad Santa 2, most people will always remember him as the guy who loves his French-fried potaters.