Join the Dead is a common Instant card from The Lost Caverns of Ixalan (LCI), collector number 110. Current market price: $0.17 (foil $0.24), TCGplayer market prices via Scryfall.
Target creature gets -5/-5 until end of turn. Descend 4 — That creature gets -10/-10 until end of turn instead if there are four or more permanent cards in your graveyard.