Wormfang Manta, Doorkeeper Thrull, and The Mind Stone

Prerequisites

• Wormfang Manta on the battlefield
• Doorkeeper Thrull on the battlefield
• The Mind Stone on the battlefield

Steps

1. Blink Wormfang Manta using The Mind Stone
2. Wormfang Manta's first ability won't trigger due to Doorkeeper Thrull
3. Wormfang Manta's second ability triggers, causing you to take an extra turn after this one
4. Repeat each turn

Results

• Infinite turns
• Lock