Riku of Two Reflections | Worldgorger Dragon

Cards

Worldgorger Dragon in hand.
Riku of Two Reflections on the battlefield.
You control any number of permanents that enter the battlefield untapped and can tap to produce at least ({1} magic symbol) ({G} magic symbol) ({U} magic symbol) .
({3} magic symbol) ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) available.

Cast
Worldgorger Dragon by paying ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Worldgorger Dragon enters the battlefield, triggering its first ability and
Riku's second ability.
Holding priority, activate any number of permanents by tapping them, adding at least ({1} magic symbol) ({G} magic symbol) ({U} magic symbol) .
Resolve the
Riku trigger, causing you to pay ({G} magic symbol) ({U} magic symbol) to create a token copy of
Worldgorger Dragon.
The token
Worldgorger Dragon enters the battlefield, triggering its first ability, exiling all other permanents you control.
The nontoken
Worldgorger Dragon leaves the battlefield, triggering its second ability, returning nothing from exile to the battlefield.
Resolve the
Worldgorger Dragon trigger from step 2, exiling the token
Worldgorger Dragon.
The token
Worldgorger Dragon leaves the battlefield, triggering its second ability, returning all permanents exiled with it to the battlefield.
Repeat from step 2.