Dockside of the Roil

When Dockside Extortionist enters the battlefield, create X Treasure tokens, where X is the number
of artifacts and enchantments your opponents
control.
Treasurefall — Whenever a treasure enters the battlefield under your control, if it's the second
time, add {w}{u}{b}{r}{g}. If it's the third time, exile Dockside of the Roil and it return it to the
battlefield under an opponents control.