Yasharn, Implacable Earth is a rare Legendary Creature — Elemental Boar card from Zendikar Rising Promos (PZNR), collector number 240p. Current market price: $0.42 (foil $0.64), TCGplayer market prices via Scryfall.
When Yasharn enters, search your library for a basic Forest card and a basic Plains card, reveal those cards, put them into your hand, then shuffle. Players can't pay life or sacrifice nonland permanents to cast spells or activate abilities.