Stalwart Successor + Woodfall Primus + Phantom Train

Stalwart Successor

Woodfall Primus

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Woodfall Primus
2. When Woodfall Primus dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Woodfall Primus enters, it and Stalwart Successor trigger.
4. Resolve the Woodfall Primus trigger, destroying a noncreature permanent.
5. Resolve the Stalwart Successor trigger, putting a +1/+1 counter on Woodfall Primus
6. Resolve the Phantom Train ability.
7. Repeat.

This clever loop uses Phantom Train's sacrifice ability to feed Woodfall Primus directly into the graveyard, where its persist mechanic normally brings it back with a -1/+1 counter. However, because Stalwart Successor is watching for the first time counters are placed on a creature each turn, that entering -1/+1 counter triggers its ability to add a matching +1/+1 counter instead. These opposing counters immediately annihilate each other through state-based actions, leaving Woodfall Primus entirely clean of -1/+1 counters and ready to be sacrificed all over again. As this cycle repeats, Woodfall Primus enters the battlefield endlessly to trigger its destruction ability over and over, wiping away every noncreature permanent your opponents control while continuously pumping up Phantom Train with infinite +1/+1 counters.