Altered Ego 
Creature — Shapeshifter
This spell can't be countered. You may have this creature enter as a copy of any creature on the battlefield, except it enters with X additional +1/+1 counters on it.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL