Kotis, Sibsig Champion + Altar of Dementia + Eternal Witness + Extra Turn Spell - GY on Resolution

Prerequisites

• You have enough mana available each turn to cast the extra turn spell and enough mana each extra turn to cast Eternal Witness.
• You have not cast a spell using Kotis
• Extra Turn Spell - GY on Resolution

Steps

1. 1Cast the extra turn spell by paying its mana cost, causing you to take an extra turn after this one.
2. 2Move to your extra turn.
3. 3Activate Altar of Dementia by sacrificing Eternal Witness, causing you to mill cards equal to Eternal Witness's power.
4. 4Cast Eternal Witness from your graveyard by paying its mana cost and exiling three other cards from your graveyard, ensuring not to exile the extra turn spell.
5. 5When Eternal Witness enters the battlefield, it triggers, returning the extra turn spell from your graveyard to your hand.
6. 6Repeat.

Effects

• Lock
• Near-infinite turns