Vesperlark, Activated Sleeper, and Phyrexian Altar

Prerequisites

• Vesperlark on the battlefield
• Activated Sleeper in the graveyard
• Phyrexian Altar on the battlefield

Steps

1. Activate Phyrexian Altar by sacrificing Vesperlark, adding one mana of any color
2. When Vesperlark dies, it triggers, returning Activated Sleeper from your graveyard to the battlefield as a copy of Vesperlark
3. Activate Phyrexian Altar by sacrificing Activated Sleeper, adding one mana of any color
4. When Activated Sleeper dies, it triggers, returning Activated Sleeper from your graveyard to the battlefield as a copy of Vesperlark
5. Repeat from step 3

Results

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