Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, Ashnod's Altar, and Clockwork Hydra

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Ashnod's Altar on the battlefield
• Clockwork Hydra on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Clockwork Hydra
2. When Clockwork Hydra dies, its persist ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter on it due to its replacement effect
3. Repeat

Results

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