Im so happy this post is here!
So I have quite a few Ideas for Dungeon Mobs.
I will be putting all of my Ideas in list form since I find its the easiest way to put all ideas down.
Have Mob Boss be able to-
*Multiply into actual fighting targets.
*Multiply into Mirror Images
*Be able to copy skins as death mentioned to me earlier today. (His Idea)
*Be able to summon different for help. (maybe as like last stand)
*Be able to deflect attacks.
*Be able to freeze players (maybe making them invulnerable to attack while frozen)
*Be able to counter attacks.
*Be able to surprise attack.
*Be able to maybe summon gravel or sand on top of players so it falls on them.
*Be able to open holes underneath player like txt or creepers do without causing damage.
*Be able to spit potions.
*Be able to summon fireballs toward ground like rain.
Have environment be able to-
*Shift up and down
*Open Lava pits at random locations
*Freeze and thaw over water periodically.
*Trap people in glass boxes. (so they can watch their teammates suffer
*Minecart chase boss when hurt.
Thats about all I have right now but will let you know if I have some more Ideas haha.