Gwenna, Eyes of Gaea is a rare Legendary Creature — Elf Druid Scout card from The Brothers' War Promos (PBRO), collector number 185p. Current market price: $5.68 (foil $6.89), TCGplayer market prices via Scryfall.
{T}: Add two mana in any combination of colors. Spend this mana only to cast creature spells or activate abilities of creature sources. Whenever you cast a creature spell with power 5 or greater, put a +1/+1 counter on Gwenna and untap it.