Orvar, the Scheme-Thief

Changeling

{u}{u}{t}: Create a 1/1 Shapeshifter token with Changeling. Then target opponent gains control of a shapeshifter you control.

Tap a shapeshifter you own but do not control: It's controller exiles the top card of their library. Both you and that player may cast cards exiled this way. You may substitute blue mana for the colored mana cost of cards exiled this way.