Grave Betrayal is a rare Enchantment card from Return to Ravnica (RTR), collector number 67. Current market price: $3.20 (foil $9.81), TCGplayer market prices via Scryfall.
Whenever a creature you don't control dies, return it to the battlefield under your control with an additional +1/+1 counter on it at the beginning of the next end step. That creature is a black Zombie in addition to its other colors and types.