Gravekeeper's Ambusher (SBLS-EN022) [Speed Duel: Arena of Lost Souls]

When this card is flipped face-up: You can target 1 card in your opponent's GY; place that target on the bottom of their Deck. If this card is sent from the field to the GY after being flipped face-up: You can target 1 "Necrovalley" card in your GY; add that target to your hand. This card's effects cannot be negated by the effect of "Necrovalley".