Tenacious Dead, Phyrexian Altar, Sifter of Skulls, and Blood Artist

Prerequisites

• Tenacious Dead on the battlefield
• Phyrexian Altar on the battlefield
• Sifter of Skulls on the battlefield
• Blood Artist on the battlefield

Steps

1. Sacrifice Tenacious Dead to Phyrexian Altar, generating
2. Sifter of Skulls, Blood Artist, and Tenacious Dead trigger; stack the triggers to resolve in that order
3. Sifter of Skulls generates an Eldrazi Scion token; sacrifice it to generate (Blood Artist triggers again)
4. Resolve two Blood Artist triggers, draining opponent for 2
5. Resolve the Tenacious Dead trigger, paying to return it to the battlefield from the graveyard
6. Repeat the sacrifice-recursion loop, draining opponent infinitely with Blood Artist triggers

Results

• Infinite death triggers
• Infinite ETB
• Infinite lifegain
• Infinite lifegain triggers
• Infinite lifeloss
• Infinite LTB