Metamorphosis Fanatic + Karmic Guide + Yahenni, Undying Partisan

Metamorphosis Fanatic

Karmic Guide

Yahenni, Undying Partisan

How it works

1. Cast Karmic Guide by paying 3.
2. When Karmic Guide enters the battlefield, it triggers, targeting Metamorphosis Fanatic.
3. Holding priority, activate Yahenni by sacrificing Karmic Guide.
4. Resolve the Karmic Guide trigger, returning Metamorphosis Fanatic from your graveyard to the battlefield.
5. When Metamorphosis Fanatic enters the battlefield, it triggers, targeting Karmic Guide.
6. Holding priority, activate Yahenni by sacrificing Metamorphosis Fanatic.
7. Resolve the Metamorphosis Fanatic trigger, returning Karmic Guide from your graveyard to the battlefield.
8. Repeat form step 2.