Cayth, Famed Mechanist, and Carrion Feeder

Prerequisites

• Cayth, Famed Mechanist on the battlefield
• Carrion Feeder on the battlefield
• The persist creature does not have a -1/-1 counter on it

Steps

1. Activate Carrion Feeder by sacrificing the persist creature
2. When the persist creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. When the persist creature enters the battlefield, its fabricate ability triggers, putting a +1/+1 counter on it
4. Resolve the Carrion Feeder ability, putting a +1/+1 counter on it
5. Repeat

Results

• Infinite +1/+1 counters on Carrion Feeder
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers