Sisters of Stone Death is a rare Legendary Creature — Gorgon card from GRN Guild Kit (GK1), collector number 71. Current market price: $0.67, TCGplayer market prices via Scryfall.
{G}: Target creature blocks Sisters of Stone Death this turn if able. {B}{G}: Exile target creature blocking or blocked by Sisters of Stone Death. {2}{B}: Put a creature card exiled with Sisters of Stone Death onto the battlefield under your control.