Deep Dark mob waves for Centerpiece of Ancient Cities.

I don't know if y'all already have a plan for the centerpiece in deep dark cities, or maybe it is just there for looks, but I have a neat concept for it. Maybe there should be a podium where when a dragon egg is placed on it it opens a portal, not for another dimension for player, but for mobs to come through. Maybe have Waves of deep dark themed mobs that progressively get harder that try to attack the egg. Maybe have 10 - 15 rounds. If you successfully defeat the waves and the egg is still alive you get items exclusive to this event.

This post may never be seen or ignored, but I think it'd be cool nonetheless. It adds more to do after the ender dragon.