Medomai the Ageless + Alesha, Who Smiles at Death + Spark Double + Yahenni, Undying Partisan

Medomai the Ageless

Alesha, Who Smiles at Death

Spark Double

Yahenni, Undying Partisan

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 Yahenni by sacrificing Spark Double
6. Repeat each turn.