Adarkar Valkyrie, Intruder Alarm, and Viscera Seer

Prerequisites

• Adarkar Valkyrie on the battlefield
• Intruder Alarm on the battlefield
• Viscera Seer on the battlefield
• Adarkar Valkyrie does not have summoning sickness

Steps

1. Activate Adarkar Valkyrie by tapping it, targeting Viscera Seer
2. Activate Viscera Seer by sacrificing itself
3. When Viscera Seer dies, Adarkar Valkyrie triggers, returning Viscera Seer from your graveyard to the battlefield
4. When Viscera Seer enters the battlefield, Intruder Alarm triggers, untapping all creatures
5. Resolve the Viscera Seer ability, causing you to scry 1
6. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana creatures you control can produce
• Infinite sacrifice triggers
• Infinite scry 1
• Infinite untap of all creatures