kill hat - what is a kill hat in military

Kill Hat

The more Junior Drill Instructors whose primary purpose in life is to make the rest of the Drill Instructors seem mild and laid back. They will teach drill and other things here and there but primarily they are there to fuck you up.

When I got to boot camp and saw I had a big black Sergeant as our Kill Hat, it was at that moment, I knew I fucked up.