Astarion's Thirst 
Instant
Exile target creature. Put X +1/+1 counters on a commander creature you control, where X is the power of the creature exiled this way.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL