Makeshift Mannequin is a uncommon Instant card from Archenemy (ARC), collector number 20. Current market price: $0.25, TCGplayer market prices via Scryfall.
Return target creature card from your graveyard to the battlefield with a mannequin counter on it. For as long as that creature has a mannequin counter on it, it has "When this creature becomes the target of a spell or ability, sacrifice it."