Prototype Portal, Dross Scorpion, March of the Machines, and Great Furnace

Prerequisites

• Prototype Portal on the battlefield
• Dross Scorpion on the battlefield
• March of the Machines on the battlefield
• Great Furnace in exile

Steps

1. Activate Prototype Portal by paying and tapping it, creating a token copy of Great Furnace
2. The Great Furnace token enters the battlefield as a 0/0 creature due to March of the Machines, and dies as a state-based action due to having zero or less toughness
3. Dross Scorpion triggers, untapping Prototype Portal
4. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite landfall triggers
• Infinite LTB