Delver's Torch is a common Artifact — Equipment card from Adventures in the Forgotten Realms (AFR), collector number 10. Current market price: $0.31 (foil $0.15), TCGplayer market prices via Scryfall.
Equipped creature gets +1/+1. Whenever equipped creature attacks, venture into the dungeon. (Enter the first room or advance to the next room.) Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)