Requires

Steps

1. Cast Metamorphosis Fanatic by paying .
2. When Metamorphosis Fanatic enters the battlefield, it triggers, targeting Body Double.
3. Holding priority, activate Phyrexian Altar by sacrificing Metamorphosis Fanatic, adding one mana of any color.
4. Resolve the Metamorphosis Fanatic ability, returning Body Double from your graveyard to the battlefield as a copy of Metamorphosis Fanatic.
5. When Body Double enters the battlefield, it triggers, targeting Metamorphosis Fanatic.
6. Holding priority, activate Phyrexian Altar by sacrificing Body Double, adding one mana of any color.
7. Resolve the Body Double ability, returning Metamorphosis Fanatic from your graveyard to the battlefield.
8. Repeat from step 2.

Results