Omnath, Locus of the Roil is a mythic Legendary Creature — Elemental card from Core Set 2020 (M20), collector number 216. Current market price: $1.95 (foil $13.29), TCGplayer market prices via Scryfall.
When Omnath enters, it deals damage to any target equal to the number of Elementals you control. Landfall — Whenever a land you control enters, put a +1/+1 counter on target Elemental you control. If you control eight or more lands, draw a card.