Adarkar Valkyrie + Intruder Alarm + Gigantoplasm

Adarkar Valkyrie

Intruder Alarm

Gigantoplasm

How it works

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

This brilliant loop dances on the edge of the legend rule to keep your battlefield perpetually churning. By using Adarkar Valkyrie's targeted revival ability alongside Gigantoplasm—which enters as a copy of a legendary creature you control—you can continuously send one copy to the graveyard to trigger the legend rule, only for Intruder Alarm to untap Adarkar Valkyrie so she can immediately target and return the fallen copy. Because Intruder Alarm untaps all creatures whenever anything enters the battlefield, Adarkar Valkyrie is freed up to keep the loop going indefinitely, letting you wring endless entry, exit, and death triggers out of your creatures.