Mirindas asesinas - Álex de la Iglesia

A man comes into a bar in which there's only one other customer and asks the bartender to serve him a Mirinda (a Spanish orange drink). But then he refuses to pay for it, saying that the bartender had never warned him that he would have to; when the bartender insists, the man takes out a rifle and kills him. Then he asks the other customer to keep serving him more Mirindas, and therefore this other man sees himself forced to replace the bartender, for fear of what the killer will do to him if he doesn't...