Mikaeus, the Unhallowed, Pith Driller, and Lithatog

Prerequisites

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

Steps

1. Activate Lithatog's first ability 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 Lithatog ability, giving it +1/+1 until end of turn
5. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinitely large Lithatog until end of turn
• Infinite sacrifice triggers