Phantom Train, and Bioengineered Future

Prerequisites

• Phantom Train on the battlefield
• Bioengineered Future on the battlefield

Steps

1. Activate Phantom Train by sacrificing the persist creature
2. When the persist creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it and at least one +1/+1 counter on it due to Bioengineered Future
3. Remove a -1/-1 counter and a +1/+1 counter from that creature as a state-based action
4. Resolve the Phantom Train ability
5. Repeat

Results

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