Gravekeeper's Ambusher

Flash
When this card enters the battlefield, you may
return target card in an opponent's graveyard to
the bottom of their library.
When this card dies, you may return target "Necrovalley" or card that lists "Necrovalley" in
its name from your graveyard to your hand.
This card's abilities are unaffected by
"Necrovalley".