Carth the Lion is a rare Legendary Creature — Human Warrior card from Modern Horizons 2 (MH2), collector number 189. Current market price: $0.42 (foil $0.41), TCGplayer market prices via Scryfall.
Whenever Carth enters or a planeswalker you control dies, look at the top seven cards of your library. You may reveal a planeswalker card from among them and put it into your hand. Put the rest on the bottom of your library in a random order. Planeswalkers' loyalty abilities you activate cost an additional [+1] to activate.