The Prydwen, Steel Flagship, Nim Deathmantle, and Ashnod's Altar

Prerequisites

• The Prydwen, Steel Flagship on the battlefield
• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• You control at least one other nontoken artifact creature

Steps

1. Activate Ashnod's Altar by sacrificing another nontoken artifact creature, adding
2. When the artifact creature dies, Nim Deathmantle triggers, causing you to pay to return the artifact creature from your graveyard to the battlefield, and attach Nim Deathmantle to it
3. When the artifact creature enters the battlefield, The Prydwen triggers, creating a 2/2 Human Knight creature token
4. Activate Ashnod's Altar by sacrificing the Human Knight, adding
5. Repeat

Results

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