Ygra, Eater of All, Cauldron Familiar, Nether Traitor, and Phyrexian Altar

Prerequisites

• Ygra, Eater of All on the battlefield
• Cauldron Familiar on the battlefield
• Nether Traitor in the graveyard
• Phyrexian Altar on the battlefield

Steps

1. Activate Phyrexian Altar by sacrificing Cauldron Familiar, adding
2. When Cauldron Familiar dies, Ygra and Nether Traitor trigger
3. Resolve the Ygra trigger, putting two +1/+1 counters on it
4. Resolve the Nether Traitor trigger, causing you to pay to return it from your graveyard to the battlefield
5. Activate Cauldron Familiar by sacrificing Nether Traitor
6. Ygra triggers, putting two +1/+1 counters on it
7. Resolve the Cauldron Familiar ability, returning it from your graveyard to the battlefield
8. When Cauldron Familiar enters the battlefield, it triggers, causing you to gain 1 life and each opponent to lose 1 life
9. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite lifegain triggers
• Infinite lifegain
• Infinite lifeloss
• Infinite +1/+1 counters on a creature