Flitwing, Lyev Detective, Ulvenwald Mysteries, and Phantom Train

Prerequisites

• Flitwing, Lyev Detective on the battlefield
• Ulvenwald Mysteries on the battlefield
• Phantom Train on the battlefield

Steps

1. Activate Phantom Train by sacrificing a Clue
2. Ulvenwald Mysteries' second ability triggers, creating a Clue token due to Flitwing
3. Resolve the Phantom Train ability, putting a +1/+1 counter on Phantom Train and causing it to become a creature until end of turn Repeat

Results

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