Hulking Metamorph + Felidar Guardian

Prerequisites

You have enough mana to cast Hulking Metamorph.

Steps

1. Cast Hulking Metamorph by paying its mana cost, choosing to have it enter the battlefield as a copy of Felidar Guardian
2. When Hulking Metamorph enters the battlefield, it triggers, blinking Felidar Guardian.
3. When Felidar Guardian enters the battlefield, it triggers, blinking Hulking Metamorph. Choose to have Hulking Metamorph enter the battlefield as a copy of Felidar Guardian.
4. Repeat from step 2.