Runed Halo is a rare Enchantment card from Shadowmoor (SHM), collector number 21. Current market price: $0.36 (foil $1.30), TCGplayer market prices via Scryfall.
As this enchantment enters, choose a card name. You have protection from the chosen card name. (You can't be targeted, dealt damage, or enchanted by anything with that name.)