Bladewing the Risen, and Deepfathom Echo

Prerequisites

• Bladewing the Risen on the battlefield
• Deepfathom Echo in hand

Steps

1. Cast Deepfathom Echo by paying its mana cost, choosing to have it enter the battlefield as a copy of Bladewing
2. Put Bladewing into your graveyard due to the legend rule
3. Deepfathom Echo's enter-the-battlefield ability triggers, returning Bladewing from your graveyard to the battlefield
4. Put Bladewing into your graveyard due to the legend rule
5. Bladewing's enter-the-battlefield ability triggers, returning it from your graveyard to the battlefield
6. Repeat from step 4

Results

• Infinite LTB
• Infinite ETB
• Infinite death triggers