I Am Untouchable is a common Ongoing Scheme card from Duskmourn: House of Horror Commander (DSC), collector number 336. Current market price: $0.33, TCGplayer market prices via Scryfall.
(An ongoing scheme remains face up until it's abandoned.) You and permanents you control have hexproof. When combat damage is dealt to you, create a 4/4 colorless Scarecrow artifact creature token with vigilance, then abandon this scheme.