Prototype Portal, Dross Scorpion, Grinding Station, and Cathodion

Prerequisites

• Prototype Portal on the battlefield
• Dross Scorpion on the battlefield
• Grinding Station on the battlefield
• Cathodion on the battlefield
• undefined available

Steps

1. Activate Prototype Portal by paying and tapping it, creating a token copy of Cathodion
2. When the token Cathodion enters, Grinding Station triggers, untapping itself
3. Activate Grinding Station by sacrificing Cathodion and tapping it
4. When Cathodion dies, Cathodion and Dross Scorpion trigger
5. Resolve the Cathodion trigger, adding
6. Resolve the Dross Scorpion trigger, untapping Prototype Portal
7. Resolve the Grinding Station ability, causing target player to mill three cards
8. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite mill
• Infinite self-mill