Raids and New Realms

So recently I've  been having a lot of fun with Destiny 2, more specifically the raids that the game provides. I also enjoy the grind leading up to the raid. Such as leveling and obtaining gear to fit your play-style.

Anyway, I thought it might be interesting to add something like this in Minecraft. I can imagine hopping on my realm with my buddies, gathering resources and preparing for some really big boss. I think it could be super fun. And, I think it could be coupled with another realm. Obviously if you guys decide to do this you can come up with whatever realm you'd like but, this is how I envision it playing out:

Your and your friends decide to reset and make new world. Once you load in, you see this big volcano in the distance. But you notice something's off about it. Instead of having fire and lava coming out of it, you see super icy clouds spewing out of it. Kind of like a harsh light-blue fog. You and your friends are intrigued and decide they want to venture out and see what this thing is. So you all start to gather resources and prepare for the journey. Once you've finished preparing and made the long trip to the icy volcano, you see can see the huge hole in the side of the volcano. Almost like a man-made entrance. Your group walks in, and out of nowhere, the ice collapses sealing the entrance/exit. You hear what you think is the shattering of glass, you look up and see a giant spider made of ice detaching itself from the inside wall of the volcano. (insert boss mechanics here yada yada yada). After defeating the monster the light blue fog starts to become less and less harsh, and eventually fades away. In the middle of the volcano there's a pit, where the fog had previously been coming from. You see a icy web, kinda looks like a wall of broken glass. You and your friends decide to make the figurative and literal leap into the pit. Once you go through you're teleported to an icy realm with new creatures and ores, new auto-generated structures, and more importantly, the anticipation of exploring it all with your friends.

Obviously it doesn’t have to be exactly like this, just something that I came up with that I think could be cool. Doesn’t even have to be an icy realm, or a giant spider. I just want a big raid-boss to fight, and upon defeating, unlocking a new world to explore with your friends.