Death Knight Soul Reaper

{1}{b}{t}: Destroy target tapped creature.
{x}: Deal X damage to target player.
{b}{g}: Death Knight soul reaper gets +1/+1 until the end of turn.
{r}{r}: Death Knight soul reaper gets first strike until the end of turn.
{b}{b}{t}: Return a zombie type creature from your graveyard back in to play.