Phantasmal Image in exile (Phantasmal Image exiled by Wormfang Drake).
Wormfang Drake on the battlefield.
Mirror Image in hand.
({2} magic symbol) ({U} magic symbol) available.
Steps
Cast Mirror Image by paying ({2} magic symbol) ({U} magic symbol) , choosing to have it enter the battlefield as a copy of Wormfang Drake.
When Mirror Image enters the battlefield, its first ability triggers, exiling Wormfang Drake.
When Wormfang Drake leaves the battlefield, its second ability triggers, returning Phantasmal Image to the battlefield as a copy of Mirror Image, thus making it a copy of Wormfang Drake.
When Phantasmal Image enters the battlefield, its first ability triggers, exiling Mirror Image.
When Mirror Image leaves the battlefield, its second ability triggers, returning Wormfang Drake from exile to the battlefield.
When Wormfang Drake enters the battlefield, its first ability triggers, exiling Phantasmal Image.
When Phantasmal Image leaves the battlefield, its second ability triggers, returning Mirror Image to the battlefield as a copy of Wormfang Drake.