Medomai the Ageless + Alesha, Who Smiles at Death + Spark Double + Altar of Dementia

Medomai the Ageless

Alesha, Who Smiles at Death

Spark Double

Altar of Dementia

How it works

1. Declare Alesha as an attacker.
2. Alesha triggers, causing you to pay U/BU/B to return Spark Double from your graveyard to the battlefield tapped and attacking as a nonlegendary copy of Medomai the Ageless.
3. Deal combat damage using Spark Double.
4. Spark Double triggers, causing you to take an extra turn after this one.
5. Activate Altar of Dementia by sacrificing Spark Double
6. Repeat each turn.