Ulamog's Dreadsire, Thornbite Staff, and Phantom Train

Prerequisites

• Ulamog's Dreadsire on the battlefield
• Thornbite Staff on the battlefield
• Phantom Train on the battlefield

Steps

1. Activate Ulamog's Dreadsire by tapping it, creating a 10/10 Eldrazi creature tokens
2. Activate Phantom Train by sacrificing the Eldrazi token
3. When the Eldrazi token dies, Ulamog's Dreadsire triggers, untapping Ulamog's Dreadsire
4. Resolve the Phantom Train ability Repeat

Results

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