Clone, and Felidar Guardian

Prerequisites

• Clone in hand
• Felidar Guardian on the battlefield

Steps

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

Results

• Infinite ETB
• Infinite LTB