Karn, the Great Creator, Teferi's Talent, Gonti's Aether Heart, and Piper Wright, Publick Reporter

Prerequisites

• Karn, the Great Creator on the battlefield
• Teferi's Talent on the battlefield
• Gonti's Aether Heart in hand
• Piper Wright, Publick Reporter on the battlefield
• Piper has power 3 or greater, does not have summoning sickness, and cannot be blocked by an opponent
• Karn has three or more loyalty counters on it
• each turn available

Steps

1. Cast Gonti's Aether Heart by paying
2. When Gonti's Aether Heart enters the battlefield, it triggers, causing you to get
3. Deal combat damage to an opponent using Piper
4. Piper triggers, creating at least three Clue tokens
5. When the Clues enter the battlefield, Gonti's Aether Heart triggers that many times, causing you to get for each Clue
6. Activate Gonti's Aether Heart by paying eight and exiling it, causing you to take an extra turn after this one
7. Activate Karn's second loyalty ability by removing two loyalty counters from it, putting Gonti's Aether Heart from exile into your hand
8. Activate a Clue by paying and sacrificing it
9. Piper triggers, putting a +1/+1 counter on a creature you control
10. Resolve the Clue ability, causing you to draw a card
11. Teferi's Talent triggers, putting a loyalty counter on Karn
12. Move to your next turn
13. During your draw step, you will draw a card
14. When you do, Teferi's Talent triggers, putting a loyalty counter on Karn
15. Repeat

Results

• Infinite turns