Urge to Feed is a uncommon Instant card from Crimson Vow Commander (VOC), collector number 139. Current market price: $0.35, TCGplayer market prices via Scryfall.
Target creature gets -3/-3 until end of turn. You may tap any number of untapped Vampire creatures you control. If you do, put a +1/+1 counter on each of those Vampires.