Prototype Portal, Dross Scorpion, and Ashnod's Altar

Prerequisites

• Prototype Portal on the battlefield
• Dross Scorpion on the battlefield
• Ashnod's Altar on the battlefield
• You have an artifact creature card with mana value 2 or less exiled by Prototype Portal
• (at most) available

Steps

1. Activate Prototype Portal by paying at most and tapping it, creating a token copy of the imprinted card
2. Activate Ashnod's Altar by sacrificing the creature token, adding
3. When the creature token dies, Dross Scorpion triggers, untapping Prototype Portal
4. Repeat

Results

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