Nightshade, Dimir Infiltrator

Nightshade, Dimir Infiltrator enters the
battlefield under the control of an opponent of
your choice and becomes a copy of a target
creature that opponent owns either on the battlefield or in the graveyard except its name is
still Nightshade, Dimir Infiltrator.
Nightshade, Dimir Infiltrator attacks each turn if
able and cannot attack its owner or planeswalkers
its owner controls.