Sylvan Might is a uncommon Instant card from Odyssey (ODY), collector number 277. Current market price: $0.18 (foil $5.63), TCGplayer market prices via Scryfall.
Target creature gets +2/+2 and gains trample until end of turn. Flashback {2}{G}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)