Carnage, Crimson Chaos, and Flesh Duplicate

Prerequisites

• Carnage, Crimson Chaos in hand
• Flesh Duplicate in the graveyard

Steps

1. Cast Carnage by paying
2. When it enters, it triggers, returning Flesh Duplicate from your graveyard to the battlefield as a copy of Carnage
3. Put Flesh Duplicate into your graveyard due to the legend rule
4. Flesh Duplicate's enter-the-battlefield ability triggers, returning itself from your graveyard to the battlefield as a copy of Carnage
5. Repeat from step 2

Results

• Infinite LTB
• Infinite ETB
• Infinite death triggers