Gyrus, Necro-Hydra

When Gyrus, Necro-Hydra attacks, mill cards equal
to its power. For each permanent put into your graveyard this way, put that many +1/+1 counters on Gyrus. Then, you may return target creature card with lesser power from your graveyard to the battlefield tapped and attacking. Shuffle it back into your library at the end of combat.

"Its many mouths were terrifying, but nothing prepared us for the hungry corpses that followed it."