Stalwart Successor + Woe Strider + Persistent Constrictor

Stalwart Successor

Woe Strider

Persistent Constrictor

How it works

1. Activate Woe Strider by sacrificing Persistent Constrictor
2. When Persistent Constrictor dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Persistent Constrictor enters, Stalwart Successor triggers, putting a +1/+1 counter on Persistent Constrictor
4. Resolve the Woe Strider ability.
5. Repeat.

This clever loop relies on Woe Strider to repeatedly sacrifice Persistent Constrictor, which triggers its persist ability to return it to the battlefield with a -1/-1 counter. Because Stalwart Successor features a triggered ability that responds the first time counters are placed on a creature each turn, the -1/-1 counter triggers it to place a +1/+1 counter on the Constrictor, which immediately annihilates both counters through state-based actions. This leaves Persistent Constrictor clean and ready to be sacrificed to Woe Strider all over again, generating an endless stream of entries, exits, deaths, and scry triggers.