Prototype Portal, Dross Scorpion, Phyrexian Altar, and Su-Chi

Prerequisites

• Prototype Portal on the battlefield
• Dross Scorpion on the battlefield
• Phyrexian Altar on the battlefield
• Su-Chi on the battlefield
• undefined available

Steps

1. Activate Prototype Portal by paying and tapping it, creating a token copy of Su-Chi
2. Activate Phyrexian Altar by sacrificing Su-Chi, adding one mana of any color
3. When Su-Chi dies, it and Dross Scorpion trigger
4. Resolve the Su-Chi trigger, adding
5. Resolve the Dross Scorpion trigger, untapping Prototype Portal
6. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite colored mana
• Infinite sacrifice triggers
• Infinite death triggers