Grim Reaper's Sprint is a rare Enchantment — Aura card from Fallout (PIP), collector number 58. Current market price: $1.35 (foil $2.82), TCGplayer market prices via Scryfall.
Morbid — This spell costs {3} less to cast if a creature died this turn. Enchant creature When this Aura enters, untap each creature you control. If it's your main phase, there is an additional combat phase after this phase. Enchanted creature gets +2/+2 and has haste.