Hostile and Boss Mobs
Hostile mobs are dangerous, aggressive mobs who will attack a player within a detected area. It is possible to have a hostile mob who does not attack a player by ensuring that game mode is in creative, with the difficultly set to easy.
Boss mobs are considered unique hostile mobs. They are tougher and more dangerous than provoked neutral mobs and hostile mobs. Boss mobs do not appear randomly in a world and need to be confronted intentionally.