Dross Scorpion, Mimic Vat, Ashnod's Altar, and Teysa Karlov

Prerequisites

• Dross Scorpion on the battlefield
• Mimic Vat on the battlefield
• Ashnod's Altar on the battlefield
• Teysa Karlov on the battlefield
• Any mana rock that generates at least one mana

Steps

1. Sacrifice Dross Scorpion to Ashnod's Altar, generating two generic mana
2. Imprint Mimic Vat with Dross Scorpion
3. Activate Mimic Vat, creating a token copy of Dross Scorpion
4. Sacrifice Dross Scorpion to Ashnod's Altar, targeting Mimic Vat and the mana rock with Dross Scorpion's two death triggers (second from Teysa)

Results

• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers