Ephemerate, Timeless Witness, and Time Warp

Prerequisites

• Ephemerate in hand
• Timeless Witness on the battlefield
• Time Warp in hand
• each turn available

Steps

1. Cast Time Warp by paying its mana cost, causing you to take an extra turn after this one
2. Cast Ephemerate by paying , blinking Timeless Witness and exiling Ephemerate
3. When Timeless Witness enters, it triggers, returning Time Warp from your graveyard to your hand
4. Move to your next turn
5. At the beginning of your upkeep, Ephemerate's rebound ability triggers, causing you to cast it from exile without paying its mana cost
6. Resolve Ephemerate, blinking Timeless Witness
7. When Timeless Witness enters, it triggers, returning Ephemerate from your graveyard to your hand
8. Repeat

Results

• Infinite turns
• Lock