Cass, Hand of Vengeance, Griffin Guide, and Ashnod's Altar

Prerequisites

• Cass, Hand of Vengeance on the battlefield
• Griffin Guide on the battlefield
• Ashnod's Altar on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing the creature with Griffin Guide attached, adding
2. When the creature dies, Cass and Griffin Guide trigger
3. Resolve the Griffin Guide trigger, creating a 2/2 Griffin creature token
4. Resolve the Cass trigger, returning Griffin Guide from your graveyard to the battlefield attached to the Griffin token
5. Repeat

Results

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