Scion of the Ur-Dragon, Colossal Grave-Reaver, and Bladewing the Risen

Prerequisites

• Scion of the Ur-Dragon on the battlefield
• Colossal Grave-Reaver in the library
• Bladewing the Risen in the library
• available

Steps

1. Activate Scion of the Ur-Dragon twice by paying
2. Resolve the first ability, searching your library for Colossal Grave-Reaver and putting it into your graveyard, and then causing Scion of the Ur-Dragon to become a copy of Colossal Grave-Reaver until end of turn
3. Resolve the second ability, searching your library for Bladewing and putting it into your graveyard, and then causing Scion of the Ur-Dragon to become a copy of Bladewing until end of turn
4. Because Scion of the Ur-Dragon was a copy of Colossal Grave-Reaver when Bladewing was put into your graveyard, it will trigger, returning Bladewing from your graveyard to the battlefield
5. Put Bladewing into your graveyard due to the legend rule
6. Bladewing triggers, returning itself from your graveyard to the battlefield
7. Repeat from step 5

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite death triggers