Just make the mob like a normal rare
Blizz killing fun again. I can't remember a more social event than us all hollering in /1 about which abilities were able to damage the boss. It was genuine community, genuine fun, and all positive. Who cares if we're farming mounts? Why did they give us 80+ mounts if each one is supposed to be hard? If the lag is the issue, maybe invest in some infrastructure so 80 players can't take down the game.
odd hes still up