Kenrith, the Returned King + Eternal Witness + Capture of Jingzhou + Ashnod's Altar

Kenrith, the Returned King

Eternal Witness

Capture of Jingzhou

Ashnod's Altar

How it works

1. Activate Ashnod's Altar by sacrificing Eternal Witness, adding CC.
2. Activate Kenrith's last ability by paying 4, returning Eternal Witness from your graveyard to the battlefield.
3. Eternal Witness enters the battlefield, returning Capture of Jingzhou from your graveyard to your hand.
4. Cast Capture of Jingzhou by paying 3, causing you to take an extra turn after this one.
5. Repeat.