Bellowing Aegisaur + Scurry Oak + Warstorm Surge

Bellowing Aegisaur

Scurry Oak

Warstorm Surge

How it works

1. Give Bellowing Aegisaur indestructible by any method.
2. Deal damage to Bellowing Aegisaur.
3. Bellowing Aegisaur triggers, putting a +1/+1 counter on each other creature you control.
4. Scurry Oak triggers, creating a 1/1 Squirrel creature token.
5. The Squirrel enters the battlefield, triggering Warstorm Surge, dealing 1 damage to Bellowing Aegisaur.
6. Repeat from step 3.

This looping engine turns a single spark of damage into an unstoppable cascade of growth and swarming tokens. Once Bellowing Aegisaur is granted indestructible, dealing damage to it triggers its Enrage ability to pump your board, which conveniently adds a +1/+1 counter to Scurry Oak. That counter generation forces Scurry Oak to spawn a 1/1 green Squirrel token, whose entry immediately triggers Warstorm Surge to deal 1 damage right back to Bellowing Aegisaur, restarting the entire cycle and continuously fueling both your army and your triggers.