Atanto, Scourge of Skareldia

Unstable 3 (At the beginning of your upkeep,
flip three coins. For every heads, put a +1/-1 counter on this creature. For every tails, put a
-1/+1 counter on it instead).
When Atanto, Scourge of Skareldia leaves
the battlefield it deals X damage to every player, where X is its power.