Mist Dragon

Something a little more challenging —When Mist Dragon enters, you may have an opponent gain control of it. If you do, it’s goaded for as long as they control it.

Flying

Well Merlina? —When Mist Dragon dies, target player that killed mist dragon creates 3 treasure tokens and Mist Dragon's owner may search their library for a legendary artifact, if a creature with Haste killed Mist Dragon, put that artifact onto the battlefield.