Adarkar Valkyrie + Intruder Alarm + Glasspool Mimic // Glasspool Shore

Adarkar Valkyrie

Intruder Alarm

Glasspool Mimic // Glasspool Shore

How it works

1. Activate Adarkar Valkyrie by tapping it, targeting any legendary creature you control.
2. Cast Glasspool Mimic by paying 2, choosing to have it enter the battlefield as a copy of the legendary creature targeted in step 1.
3. Put the legendary creature into your graveyard due to the legend rule.
4. Adarkar Valkyrie and Intruder Alarm trigger.
5. Resolve the Intruder Alarm trigger, untapping all creatures.
6. Holding priority, activate Adarkar Valkyrie by tapping it, targeting Glasspool Mimic.
7. Resolve the Adarkar Valkyrie trigger from step 4, returning the legendary creature to the battlefield from your graveyard.
8. Put Glasspool Mimic into your graveyard due to the legend rule.
9. Adarkar Valkyrie and Intruder Alarm trigger.
10. Resolve the Intruder Alarm trigger, untapping all creatures.
11. Holding priority, activate Adarkar Valkyrie by tapping it, targeting the legendary creature.
12. Resolve the Adarkar Valkyrie trigger from step 9, returning Glasspool Mimic to the battlefield from your graveyard as a copy of the legendary creature.
13. Repeat from step 3.

This brilliant loop exploits the legend rule and untap triggers to generate endless value with just three cards. By having Glasspool Mimic enter as a copy of a legendary creature you already control, the legend rule instantly sends it to the graveyard, which triggers Adarkar Valkyrie's delayed ability to return it while simultaneously causing Intruder Alarm to untap all your creatures. Because Intruder Alarm keeps Adarkar Valkyrie fresh and ready to tap again, you can endlessly resurrect your copied legend and the Mimic back and forth, letting you harvest infinite enters-the-battlefield triggers, deaths, and untapped creature activations.