Revenge bullying
Treating someone as less than human because you thought they were never anything else besides a bully. Thinking you deserve better treatment than everyone else, while treating somebody else like shit yourself.
According to some people it's okay to bully, as long as they're the ones doing it, since they know who the bullies are, and bullying someone who's a bully is right. With revenge bullying, someone can look innocent when its convenient, and look like the badass when its convienient.
Revenge bully
Someone that became a bully and a badass later in life to get back at anybody that caused them to suffer eary in life.
He/she was a revenge bully that spent the rest of his/her life trying to get back at the monsters that did what they did to him/her early in life.