So I'm currently setting up a World of Warcraft-like dungeon on my server that a decently popular YouTuber is going to play. I've completed 90% of the dungeon and I have begun work on the final boss area. Since my server is semi-vanilla, I'm looking for any kind of mechanic that could make this boss battle interesting. Whether it's using redstone, Commandblocks or something natural. I need ideas and suggestions. I'll even credit you on the server if I use your idea.
I'd love to have the time to do something to that scale, but my time is slim, so I won't be able to do a battle of that scale this time around. I need more mechanics like what Stealthman suggested, which I'm using already.