River Song, Conjurer's Bauble, Mechanized Production, and Time Stretch

Prerequisites

• River Song on the battlefield
• Conjurer's Bauble on the battlefield
• Mechanized Production on the battlefield
• Time Stretch in hand
• each turn available

Steps

1. At the beginning of your upkeep, Mechanized Production triggers, creating a token copy of Conjurer's Bauble
2. Cast Time Stretch by paying , causing you to take two extra turns after this one
3. Activate the Conjurer's Bauble token by tapping and sacrificing it, putting Time Stretch onto the bottom of your library from your graveyard, and then causing you to draw Time Stretch from the bottom of your library due to River Song
4. Repeat each other turn

Results

• Infinite turns