Standard drug dealer: "Who the fuck is that?"
Busey: "Your worst nightmare, butthorn!"
Yes. Butthorn. I have no idea what that is, but Busey uses it at least twice in the course of the film before killing people, so I guess it's pretty bad. I credit the filmmakers here for making the McGuffin not something boring like illegal drugs or guns or something, but something totally ridiculous and bad ass: a secret government robo-tank stolen by a Libyan general in Mexico.
This movie is unforgettable. I own it. You should too!