Metamorphosis Fanatic, Body Double, and Carrion Feeder

Prerequisites

• Metamorphosis Fanatic in hand
• Body Double in the graveyard
• Carrion Feeder on the battlefield

Steps

1. Cast Metamorphosis Fanatic by paying
2. When Metamorphosis Fanatic enters the battlefield, it triggers, targeting Body Double
3. Holding priority, activate Carrion Feeder by sacrificing Metamorphosis Fanatic, putting a +1/+1 counter on Carrion Feeder
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 Carrion Feeder by sacrificing Body Double, putting a +1/+1 counter on Carrion Feeder
7. Resolve the Body Double ability, returning Metamorphosis Fanatic from your graveyard to the battlefield
8. Repeat from step 2

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite +1/+1 counters on Carrion Feeder