Volgashna, the provider

When Volgashna, the provider enters the battlefield, exile up to X cards from target opponents graveyard

{3}, {t}: Put a card an opponent owns from exile into that players graveyard.

Whenever a card is put into a graveyard from exile, put a 0/1 colorless Eldrazi Spawn creature token onto the battlefield. It has "Sacrifice this creature: Add {c}"