Angel's Trumpet is a uncommon Artifact card from Urza's Legacy (ULG), collector number 121. Current market price: $3.00 (foil $23.96), TCGplayer market prices via Scryfall.
All creatures have vigilance. At the beginning of each player's end step, tap all untapped creatures that player controls that didn't attack this turn. This artifact deals damage to the player equal to the number of creatures tapped this way.