Tenacious Underdog is a rare Creature — Human Warrior card from Streets of New Capenna Promos (PSNC), collector number 97p. Current market price: $0.43 (foil $0.38), TCGplayer market prices via Scryfall.
Blitz—{2}{B}{B}, Pay 2 life. (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.) You may cast this card from your graveyard using its blitz ability.