Tenacious Dead + Phyrexian Altar + Pitiless Plunderer

Tenacious Dead

Phyrexian Altar

Pitiless Plunderer

How it works

1. Activate Phyrexian Altar by sacrificing Tenacious Dead, adding one mana.
2. When Tenacious Dead dies, it and Pitiless Plunderer trigger.
3. Resolve the Pitiless Plunderer trigger, creating a Treasure token.
4. Activate that Treasure token by tapping and sacrificing it, adding .
5. Resolve the Tenacious Dead trigger, paying 1 to return it to the battlefield from your graveyard.
6. Repeat.