Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, Sightless Ghoul, and Phantom Train

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Sightless Ghoul on the battlefield
• Phantom Train on the battlefield

Steps

1. Activate Phantom Train by sacrificing Sightless Ghoul When Sightless Ghoul dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
2. Activate Phantom Train by sacrificing Sightless Ghoul When Sightless Ghoul dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Resolve both Phantom Train abilities from step 1 and 3
4. Repeat

Results

• Infinite +1/+1 counters on a creature
• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite sacrifice triggers