Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, Phyrexian Altar, and Pyreheart Wolf

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Phyrexian Altar on the battlefield
• Pyreheart Wolf on the battlefield

Steps

1. Activate Phyrexian Altar by sacrificing Pyreheart Wolf When Pyreheart Wolf dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
2. Activate Phyrexian Altar by sacrificing Pyreheart Wolf When Pyreheart Wolf dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Pyreheart Wolf enters and dies as a state-based action due to having 0 toughness
4. Its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
5. Repeat from step 3

Results

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