A drug addict who has had their brain fried that much that the only thing left they know how to do is smoke cigarettes.
Mate 1: What's going on up in there mate? You got nothing but fuckin ciggy butts up there now. You got a ciggy butt brain.
Mate 2: No I don't
Mate 1: That's what they are going to call you man, they are going to call you man.