Stalwart Successor, Woodfall Primus, and Phantom Train

Prerequisites

• Stalwart Successor on the battlefield
• Woodfall Primus on the battlefield
• Phantom Train on the battlefield

Steps

1. Activate Phantom Train by sacrificing Woodfall Primus When Woodfall Primus dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
2. When Woodfall Primus enters, it and Stalwart Successor trigger
3. Resolve the Woodfall Primus trigger, destroying a noncreature permanent
4. Resolve the Stalwart Successor trigger, putting a +1/+1 counter on Woodfall Primus Resolve the Phantom Train ability
5. Repeat

Results

• Infinite +1/+1 counters on a creature
• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite sacrifice triggers
• Destroy any number of noncreature permanents
• Lock