Skeleton Ship, Intruder Alarm, Flayer of the Hatebound, and Ashnod's Altar

Prerequisites

• Skeleton Ship on the battlefield
• Intruder Alarm on the battlefield
• Flayer of the Hatebound on the battlefield
• Ashnod's Altar on the battlefield
• Skeleton Ship does not have summoning sickness
• Flayer of the Hatebound does not have a +1/+1 counter on it

Steps

1. Activate Ashnod's Altar by sacrificing Flayer of the Hatebound, adding
2. Flayer of the Hatebound dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it
3. Flayer of the Hatebound enters the battlefield, triggering itself and Intruder Alarm
4. Resolve the Flayer of the Hatebound trigger, dealing damage equal to its power to any target
5. Resolve the Intruder Alarm trigger, untapping all creatures
6. Activate Skeleton Ship by tapping it, putting a -1/-1 counter on Flayer of the Hatebound
7. Repeat

Results

• Infinite colorless mana
• Infinite damage
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana creatures you control can produce
• Infinite sacrifice triggers
• Infinite untap of all creatures