Name:Cloudkill
ManaCost:4 B B
Types:Sorcery
A:SP$ PumpAll | ValidCards$ Creature | NumAtt$ -X | NumDef$ -X | SpellDescription$ All creatures get -X/-X until end of turn, where X is the greatest mana value of a commander you own on the battlefield or in the command zone.
SVar:X:Count$ValidBattlefield,Command Card.IsCommander+YouOwn$GreatestCMC
AI:RemoveDeck:NonCommander
Oracle:All creatures get -X/-X until end of turn, where X is the greatest mana value of a commander you own on the battlefield or in the command zone.