“BITE YOUR HEAD OFF”
Until now “bite your head off” was just an expression. No one does that really. It is a metaphor for “stay out of my way.” An expression of anger… at you… at me… at something… The what doesn’t generally matter. No “wrong-doing” need actually occur between biter and bitee. To bite your head off is an act of displacement, transferring aggression between brother and sister because mom just scolded one of you.
Until now... when I yelled at my dog Rover to "COME HERE; BAD BOY!” The next dog (her name is Addie) to get in his way after being duly humiliated by me got more than just a show of teeth. I was shocked. Rover is usually so quiet. I used to call him a beta dog until someone corrected me and said that isn't a term. But alpha dog is a term and Addie is an alpha dog until Rover set her straight by barring his teeth and growling then lunging at her face to bite it off for simply sniffing and welcoming him to the dog walk.
Bite your head off. I get it. Even dogs pass it on.