Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, Geralf's Messenger, and Umbral Collar Zealot

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Geralf's Messenger on the battlefield
• Umbral Collar Zealot on the battlefield

Steps

1. Activate Umbral Collar Zealot by sacrificing Geralf's Messenger When Geralf's Messenger dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
2. When Geralf's Messenger enters, it triggers, causing an opponent to lose 2 life
3. Activate Umbral Collar Zealot by sacrificing Geralf's Messenger When Geralf's Messenger dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
4. When Geralf's Messenger enters, it triggers, causing an opponent to lose 2 life
5. Resolve both Umbral Collar Zealot abilities from step 1 and 4
6. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite lifeloss
• Infinite sacrifice triggers
• Infinite surveil