Masterpiece Thief

When Masterpiece Thief enters the battlefield,
gain control of target masterpiece an opponent controls as long as Masterpiece Thief is on the battlefield.
At the beginning of your upkeep, put a lore
counter on a masterpiece you control but don't
own. Then, if there are five or more lore
counters on that masterpiece, create a copy of it. Sacrifice Masterpiece Thief.