Akawalli, the Seething Tower is a uncommon Legendary Creature — Fungus card from The Lost Caverns of Ixalan (LCI), collector number 298. Current market price: $0.19 (foil $0.23), TCGplayer market prices via Scryfall.
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.