Mass Obliteration

Target creature you control gets +5/+5 until the end of turn.
At the beginning of the next end step, if Mass Obliteration is in your graveyard, exile it. Then each creature gets -5/-5 until the end of turn.
"This world has seen far too much calamity. I am the Omega of cataclysm, and this world will be renewed."
-Sentry