Agrus Kos, Spirit of Justice is a mythic Legendary Creature — Spirit Detective card from Murders at Karlov Manor Promos (PMKM), collector number 184p. Current market price: $1.25, TCGplayer market prices via Scryfall.
Double strike, vigilance Whenever Agrus Kos enters or attacks, choose up to one target creature. If it's suspected, exile it. Otherwise, suspect it. (A suspected creature has menace and can't block.)