Dross Scorpion, Retrofitter Foundry, and Ashnod's Altar

Prerequisites

• Dross Scorpion on the battlefield
• Retrofitter Foundry on the battlefield
• Ashnod's Altar on the battlefield
• available

Steps

1. Activate Retrofitter Foundry's second ability by paying and tapping it, creating a 1/1 Servo artifact creature token
2. Activate Ashnod's Altar by sacrificing the Servo, adding
3. When the Servo dies, Dross Scorpion triggers, untapping Retrofitter Foundry
4. Repeat

Results

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