Mirror Image + Felidar Guardian

Prerequisites

You have enough mana to cast Mirror Image.

Steps

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