Curse of Shaken Faith is a rare Enchantment — Aura Curse card from Innistrad: Midnight Hunt Promos (PMID), collector number 134p. Current market price: $0.42 (foil $0.49), TCGplayer market prices via Scryfall.
Enchant player Whenever enchanted player casts a spell other than the first spell they cast each turn or copies a spell, this Aura deals 2 damage to them.