Mikaeus, the Unhallowed, Spike Feeder, and Carrion Feeder

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Spike Feeder on the battlefield
• Carrion Feeder on the battlefield
• Spike Feeder has no +1/+1 counters on it

Steps

1. Activate Carrion Feeder by sacrificing Spike Feeder
2. Spike Feeder's undying ability triggers, returning itself to the battlefield with a +1/+1 counter on it
3. Resolve the Carrion Feeder ability, putting a +1/+1 counter on it
4. Activate Spike Feeder's second ability three times by removing three +1/+1 counters from it, causing you to gain six life
5. Repeat

Results

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