River Song, Cybernetic Specialist, and Time Stretch

Prerequisites

• River Song on the battlefield
• Cybernetic Specialist on the battlefield
• Time Stretch in hand
• each other turn available

Steps

1. Cast Time Stretch by paying its mana cost, causing you to take an extra turn after this one
2. Activate Cybernetic Specialist by paying and tapping it, causing you to put Time Stretch on the bottom of your library from your graveyard
3. Move to your next turn, drawing Time Stretch from the bottom of your library due to River Song during your draw step
4. Move to your second extra turn and repeat

Results

• Infinite turns
• Lock
• Skip your draw steps