Okay, this is one of the most amazing things I've ever seen, and I personally believe it will liven up the server and make it more diverse than other servers. Just watch the video, and be amazed. Link:
This is a command from a Command block and I would imagine this would mess up many peoples houses and destroy the landscape it would just be hard to control and would just mess up servers such as survival. Peoples houses will be destroyed and it would just destroy the landscape but if this is possible to be set up in factions this would be Cool but not in servers like survival,skyblock stuff like that. If this does get implemented a plugin for custom mobs would be better instead of a command block command. Thanks for reading.