Adarkar Valkyrie, Intruder Alarm, and Woe Strider

Prerequisites

• Adarkar Valkyrie on the battlefield
• Intruder Alarm on the battlefield
• Woe Strider on the battlefield
• Adarkar Valkyrie does not have summoning sickness
• You control at least one additional nontoken creature

Steps

1. Activate Adarkar Valkyrie by tapping it, targeting another nontoken creature you control
2. Activate Woe Strider by sacrificing the creature targeted in step 1
3. When the creature dies, Adarkar Valkyrie triggers, returning the sacrificed creature from your graveyard to the battlefield
4. When the creature enters the battlefield, Intruder Alarm triggers, untapping all creatures
5. Resolve the Woe Strider ability, causing you to scry 1
6. Repeat

Results

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