Spark Double + Felidar Guardian

Prerequisites

You have enough mana to cast Spark Double.

Steps

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