Melira, Sylvok Outcast is a rare Legendary Creature — Human Scout card from New Phyrexia (NPH), collector number 115. Current market price: $3.81 (foil $32.80), TCGplayer market prices via Scryfall.
You can't get poison counters. Creatures you control can't have -1/-1 counters put on them. Creatures your opponents control lose infect.