Adarkar Valkyrie + Intruder Alarm + Clever Impersonator

Adarkar Valkyrie

Intruder Alarm

Clever Impersonator

How it works

1. Activate Adarkar Valkyrie by tapping it, targeting any legendary creature you control.
2. Cast Clever Impersonator 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 Clever Impersonator.
7. Resolve the Adarkar Valkyrie trigger from step 4, returning the legendary creature to the battlefield from your graveyard.
8. Put Clever Impersonator 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 Clever Impersonator to the battlefield from your graveyard as a copy of the legendary creature.
13. Repeat from step 3.

This brilliant loop plays out as an endless, cyclical exchange of identities between your original legendary creature and a Clever Impersonator copying it, with the legend rule acting as the very catalyst for their demise. Because Intruder Alarm turns every new entry into a mass untap event, Adarkar Valkyrie remains constantly ready to tap and rescue whichever copy just hit the graveyard. The Valkyrie's delayed trigger ensures that the chosen legend is endlessly recycled back and forth, generating infinite enter-the-battlefield triggers and untapping your entire board along the way.