Mikaeus, the Unhallowed, Pith Driller, and Carrion Feeder

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Pith Driller on the battlefield
• Carrion Feeder on the battlefield
• Pith Driller does not have a +1/+1 counter on it

Steps

1. Activate Carrion Feeder by sacrifiicing Pith Driller
2. When Pith Driller dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
3. When Pith Driller enters the battlefield, it 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