Shifting Grunnmork

Changeling
As Shifting Grunnmork enters the battlefield, you
may reveal a Shapeshifter card from your hand,
Shifting Grunnmork enters the battlefield tapped
unless you revealled a card this way or you
control a Shapeshifter.
{1}{g}{u}{u}, {t}: Target shapeshifter you control
becomes a copy of another target creature until
the end of turn.