Moritte of the Frost, and Felidar Guardian

Prerequisites

• Moritte of the Frost in hand
• Felidar Guardian on the battlefield

Steps

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

Results

• Infinite LTB
• Infinite ETB