Akawalli, the Seething Tower — The Lost Caverns of Ixalan #298

Descend 4 — As long as there are four or more permanent cards in your graveyard, Akawalli gets +2/+2 and has trample.

Descend 8 — As long as there are eight or more permanent cards in your graveyard, Akawalli gets an additional +2/+2 and can't be blocked by more than one creature.