Lagrella, the Magpie, Karmic Guide, and Phyrexian Altar

Prerequisites

• Lagrella, the Magpie in hand or in the command zone
• Karmic Guide on the battlefield
• Phyrexian Altar on the battlefield
• plus enough mana to pay for commander tax, if applicable available

Steps

1. Cast Lagrella by paying and commander tax, if applicable
2. When Lagrella enters the battlefield, it triggers, exiling Karmic Guide until Lagrella leaves the battlefield
3. Activate Phyrexian Altar by sacrificing Lagrella, adding one mana of any color
4. If Lagrella is your commander, choose not to return it to the command zone from your graveyard
5. When Lagrella leaves the battlefield, Karmic Guide is returned to the battlefield from exile
6. When Karmic Guide enters the battlefield, it and Lagrella triggers
7. Resolve the Lagrella trigger, putting two +1/+1 counters on Karmic Guide
8. Resolve the Karmic Guide trigger, returning Lagrella from your graveyard to the battlefield
9. Repeat from step 2

Results

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