Requires

The Sixth Doctor must be on the battlefield. Karn's Temporal Sundering must be in hand. Isochron Scepter must be on the battlefield. Unsubstantiate must be in exile (exiled by Isochron Scepter). Mana needed: each turn

Steps

1. Cast Karn's Temporal Sundering by paying .
2. The Sixth Doctor triggers, copying Karn's Temporal Sundering.
3. Resolve the copy of Karn's Temporal Sundering, causing you to take an extra turn after this one.
4. Holding priority, activate Isochron Scepter by paying and tapping it, casting a copy of Unsubstantiate without paying its mana cost.
5. Resolve Unsubstantiate, returning the original Karn's Temporal Sundering to your hand.
6. Repeat each turn.

Results