You Are Unworthy of Mercy is a common Scheme card from Duskmourn: House of Horror Commander (DSC), collector number 359. Current market price: $0.32, TCGplayer market prices via Scryfall.
When you set this scheme in motion, each opponent sacrifices a nonland permanent of their choice. If you control six or more lands, each opponent sacrifices three nonland permanents of their choice instead.