Urge to Feed 
Instant
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.
Legality
standardNOT LEGALpioneerNOT LEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL