Spawn boss(es) on player when most of the map is cleared map mod

This could work for POE in general and make mapping a bit more dynamic. When the player clears most of the map, the boss will spawn near them. This could be a mod that can be rolled on map.

When the boss spawns, he can upgrade, revive, or interact with nearby enemies, corpses, league mechanics, or bosses; potentially making the battle harder and another chance at better loot. Let me know what you guys think about this mod idea.