Death Pulse is a uncommon Instant card from Onslaught (ONS), collector number 137. Current market price: $0.20 (foil $1.04), TCGplayer market prices via Scryfall.
Target creature gets -4/-4 until end of turn. Cycling {1}{B}{B} ({1}{B}{B}, Discard this card: Draw a card.) When you cycle this card, you may have target creature get -1/-1 until end of turn.