Ok, another idea I had is maybe a one command for a water park/water slide and have several different kinds of spawn eggs for them! Or maybe a command that will randomly spawn "nukes" in your world every 15 minutes, and the air around it will poison/wither you, but if you can survive to the epicenter, there is a chest with epic loot! Or you could incorporate the "nuke" idea with a command that (instead of earthquakes or something) could spawn the "nukes" , a stampede of cows, something like "spontaneous combustion" if you stop moving, or a horde of termites (aka endermites) that will "eat away" blocks around them as they move around! (or you could use silverfish) Ok sorry about the super long comments, but I can't figure out how to make a mod pack or complicated commands, so I'm bursting with ideas!

WOW. This is amazing: May I suggest an idea? What if you could do (idk if anyone has done this before) only one command: aliens and/or spaceships that can fly down from the sky during storms and break chests and steal your stuff, and sometimes "kidnap" you and bring you up somewhere! Like I said, IDK if you could do this, but something like that would be awesome. I'm guessing you could incorporate the shulkers powers into like a laser beam pulling you up into the sky. Thanks For This WONDERFUL Command!!!

You could make a truly amazing mod pack

How it's amazing to see the power of command blocks. You should team up with Jragon014

This + The Hell Difficulty you already made + Pandora's Box that you also already made = Minecraftageddon?