Adarkar Valkyrie, Hyrax Tower Scout, and Phyrexian Altar

Prerequisites

• Adarkar Valkyrie on the battlefield
• Hyrax Tower Scout in hand
• Phyrexian Altar on the battlefield
• available

Steps

1. Cast Hyrax Tower Scout with its enter the battlefield trigger targeting Adarkar Valkyrie
2. Maintaing priority, anctivate Adarkar Valkyrie's ability targeting Hyrax Tower Scout
3. Adarkar Valkyrie's ability resolves and Hyrax Tower Scout's trigger resolves untapping Adarkar Valkyrie
4. Sacrifice Hyrax Tower Scout to Phyrexian Altar
5. Adarkar Valkyrie's ability triggers and returns Hyrax Tower Scout to the battlefield
6. Repeat

Results

• Infinite colored mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers