Dark Impostor 
Creature — Vampire Assassin
: Exile target creature and put a +1/+1 counter on this creature.
This creature has all activated abilities of all creature cards exiled with it.
Legality
standardNOT LEGALpioneerNOT LEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL