The whole map is a volcano and its eruption hole is in in the center. It will shoot fireballs sometimes, and progressively, will shoot more and frecuently (Sometimes, it will shoot rocks without fire).
These fireballs will mark a signal circle to warn players so they can move and evading them.
Final act: The volcano erupts a big lava river that will cover the whole place, and the players must try to survive it climbing some magma rocks, climbing them. And progressively, the rocks used to climbing, will dissapear while these are Going Deeper in the lava river.
And its background music could be Tribal-themed/Ancient civilization, something like this: