Revivify

Each nonland card in each players graveyard's
gains flashback until the end of the turn.
The flashback cost is equal to it's manna cost.
Lands tapped for flashback costs this turn do not
untap during their controllers next untap step.
Each creature card returned from the graveyard
to the battlefield this turn, Gain decayed (It can't
block.When it attacks, sacrifice it at the end of combat)