Nebula Prowler

Whenever Nebula Prowler attacks, defending
player mills three cards.
{1}{u}{b}, exile target card from your graveyard:
Return Nebula Prowler from your graveyard to
your hand. It enters the battlefield tapped, and
doesn't untap for a number of your upkeeps
equal to the number of times Nebula Prowler
has left the graveyard.