Koll, the Forgemaster, Demonmail Hauberk, Ornithopter, and Phyrexian Walker

Prerequisites

• Koll, the Forgemaster on the battlefield
• Demonmail Hauberk on the battlefield
• Ornithopter on the battlefield
• Phyrexian Walker on the battlefield
• Demonmail Hauberk attached to Ornithopter

Steps

1. Activate Demonmail Hauberk's equip ability by sacrificing Ornithopter, targeting Phyrexian Walker
2. When Ornithopter dies, Koll triggers, returning Ornithopter from your graveyard to your hand
3. Resolve the Demonmail Hauberk ability, attaching it to Phyrexian Walker
4. Cast Ornithopter by paying
5. Activate Demonmail Hauberk's equip ability by sacrificing Phyrexian Walker, targeting Ornithopter
6. When Phyrexian Walker dies, Koll triggers, returning Phyrexian Walker from your graveyard to your hand
7. Resolve the Demonmail Hauberk ability, attaching it to Ornithopter
8. Cast Phyrexian Walker by paying
9. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers
• Infinite storm count