Intruder Alarm, and Sprout Swarm

Prerequisites

• Intruder Alarm on the battlefield
• Sprout Swarm in hand
• You control at least five untapped creatures, one of which must be green

Steps

1. Cast Sprout Swarm with buyback by tapping five untapped creatures you control, creating a 1/1 Saproling creature token and returning Sprout Swarm to your hand
2. The Saproling enters the battlefield, triggering Intruder Alarm, untapping all creatures
3. Repeat

Results

• Infinite creature tokens
• Infinite ETB
• Infinite magecraft triggers
• Infinite mana creatures you control can produce
• Infinite storm count
• Infinite untap of all creatures