Fly is a uncommon Enchantment — Aura card from Adventures in the Forgotten Realms (AFR), collector number 59. Current market price: $0.25 (foil $0.27), TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature has flying and "Whenever this creature deals combat damage to a player, venture into the dungeon." (Enter the first room or advance to the next room.)