Intruder Alarm, Stonybrook Schoolmaster, and Fatestitcher

Prerequisites

• Intruder Alarm on the battlefield
• Stonybrook Schoolmaster on the battlefield
• Fatestitcher on the battlefield
• Fatestitcher and Stonybrook Schoolmaster do not have summoning sickness

Steps

1. Activate Fatestitcher by tapping it, tapping Stonybrook Schoolmaster
2. Stonybrook Schoolmaster triggers, creating a 1/1 Merfolk Wizard creature token
3. When the Merfolk Wizard enters the battlefield, Intruder Alarm triggers, untapping all creatures
4. Repeat

Results

• Infinite creature tokens
• Infinite ETB
• Infinite mana creatures you control can produce
• Infinite untap of all creatures