Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, Phantom Train, and Arcbound Overseer

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Phantom Train on the battlefield
• Arcbound Overseer on the battlefield

Steps

1. Activate Phantom Train by sacrificing Arcbound Overseer
2. When Arcbound Overseer dies, its modular ability and persist ability trigger
3. Resolve the modular trigger, putting Arcbound Overseer's +1/+1 counters on another artifact creature
4. Resolve the persist trigger, returning Arcbound Overseer from your graveyard to the battlefield
5. It will not have a -1/-1 counter on it due to its modular ability
6. Resolve the Phantom Train ability
7. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite +1/+1 counters on artifact creatures you control
• Infinite +1/+1 counters on a creature