Lost in the Woods is a rare Enchantment card from Dark Ascension (DKA), collector number 123. Current market price: $0.31 (foil $0.52), TCGplayer market prices via Scryfall.
Whenever a creature attacks you or a planeswalker you control, reveal the top card of your library. If it's a Forest card, remove that creature from combat. Then put the revealed card on the bottom of your library.