Furnace of Amonkhet

This spell can't be countered.
At the beginning of each upkeep, put a Sunlight counter on Furnace of Amonkhet and it deals X
damage to each creature your opponents control
where X is the number of Sunlight counters on Furnace of Amonkhet.
At the beginning of each end step, if there are 8
or more Sun counters on Furnace of Amonkhet, sacrifice this card.