Hidetsugu, Devouring Chaos, Intruder Alarm, Mortuary, and Stonecoil Serpent

Prerequisites

• Hidetsugu, Devouring Chaos on the battlefield
• Intruder Alarm on the battlefield
• Mortuary on the battlefield
• Stonecoil Serpent in hand
• Hidetsugu does not have summoning sickness
• Creatures you control can tap to produce at least

Steps

1. Activate all mana-producing creatures you control by tapping them, adding at least
2. Cast Stonecoil Serpent by paying
3. Stonecoil Serpent enters the battlefield and dies as a state-based action due to having zero toughness
4. Intruder Alarm and Mortuary trigger
5. Resolve the Intruder Alarm trigger, untapping all creatures
6. Resolve the Mortuary trigger, putting Stonecoil Serpent on top of your library from your graveyard
7. Activate Hidetsugu's second ability by paying and tapping it, exiling Stonecoil Serpent from the top of your library and allowing you cast it this turn
8. Repeat

Results

• Infinite +1/+1 counters on Stonecoil Serpent
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana creatures you control can produce
• Infinite storm count
• Infinite untap of all creatures