Grenzo, Dungeon Warden, The Cauldron of Eternity, and Ashnod's Altar

Prerequisites

• Grenzo, Dungeon Warden on the battlefield
• The Cauldron of Eternity on the battlefield
• Ashnod's Altar on the battlefield
• available

Steps

1. Activate Grenzo by paying
2. Holding priority, activate Ashnod's Altar by sacrificing Grenzo, adding
3. When Grenzo dies, The Cauldron of Eternity triggers, putting Grenzo from your graveyard onto the bottom of your library
4. Resolve the Grenzo ability from step 1, causing you to put Grenzo from the bottom of your library into your graveyard, and then putting Grenzo onto the battlefield
5. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers