Altaïr Ibn-La'Ahad, Éomer, Marshal of Rohan, Ashnod's Altar, and Rukarumel, Biologist

Prerequisites

• Altaïr Ibn-La'Ahad on the battlefield
• Éomer, Marshal of Rohan in the graveyard
• Ashnod's Altar on the battlefield
• Rukarumel, Biologist on the battlefield
• Altaïr does not have summoning sickness
• An opponent cannot block and kill Altaïr
• You have at least one legendary creature card exiled with a memory counter on it
• Rukarumel on the battlefield with "Assassin" chosen

Steps

1. Declare Altaïr as an attacker
2. Altaïr triggers, exiling Éomer from your graveyard with a memory counter on it, and then creating a tapped and attacking token copy of each card you own that is exiled with a memory counter on it
3. Activate Ashnod's Altar by sacrificing another legendary creature token except Éomer, adding
4. When the creature dies, Éomer triggers, untapping all creatures you control and causing you to get an additional combat phase after this one
5. Repeat during each combat phase

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite colorless mana
• Infinite combat phases