Hylda of the Icy Crown, Intruder Alarm, Ashnod's Altar, and Rimewind Taskmage

Prerequisites

• Hylda of the Icy Crown on the battlefield
• Intruder Alarm on the battlefield
• Ashnod's Altar on the battlefield
• Rimewind Taskmage on the battlefield
• An opponent controls an untapped creature
• You control at least four snow permanents
• Rimewind Taskmage does not have summoning sickness
• available

Steps

1. Activate Rimewind Taskmage by paying and tapping it, tapping target creature an opponent controls
2. Hylda of the Icy Crown triggers, causing you to pay to create a 4/4 Elemental creature token
3. When the Elemental enters the battlefield, Intruder Alarm triggers, untapping all creatures
4. Activate Ashnod's Altar by sacrificing the Elemental, adding
5. Repeat

Results

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