Felidar Guardian, Vesperlark, and Ashnod's Altar

Prerequisites

• Felidar Guardian in hand
• Vesperlark on the battlefield
• Ashnod's Altar on the battlefield
• available

Steps

1. Cast Felidar Guardian by paying
2. When Felidar Guardian enters the battlefield, it triggers, targeting Vesperlark
3. Holding priority, activate Ashnod's Altar by sacrificing Felidar Guardian
4. Resolve the Felidar Guardian trigger, blinking Vesperlark
5. When Vesperlark leaves the battlefield, it triggers, returning Felidar Guardian from your graveyard to the battlefield
6. Repeat from step 2

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite colorless mana
• Infinite death triggers