Missy, Skirk Alarmist, Intruder Alarm, and Phyrexian Altar

Prerequisites

• Missy on the battlefield
• Skirk Alarmist on the battlefield
• Intruder Alarm on the battlefield
• Phyrexian Altar on the battlefield
• You control another nontoken nonartifact creature

Steps

1. Activate Phyrexian Altar by sacrificing another nontoken nonartifact creature, adding one mana of any color
2. When the creature dies, Missy's first ability triggers, returning the creature from your graveyard to the battlefield face down as a 2/2 Cyberman artifact creature
3. When the creature enters the battlefield, Intruder Alarm triggers, untapping all creatures
4. Activate Skirk Alarmist by tapping it, turning the creature face up
5. Repeat

Results

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