Carrion Feeder + Grazing Kelpie + Hardened Academic

Carrion Feeder

Grazing Kelpie

Hardened Academic

How it works

1. Activate Carrion Feeder by sacrificing Grazing Kelpie.
2. When Grazing Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Hardened Academic triggers, putting a +1/+1 counter on Grazing Kelpie.
4. Resolve the Carrion Feeder ability.
5. Repeat.

This clever loop turns a modest caterpillar into an unstoppable giant by weaponizing the interaction between sacrifice and resurrection. You feed Grazing Kelpie to Carrion Feeder, sending the Kelpie to the graveyard where its persist ability immediately triggers to return it with a -1/-1 counter. This departure from the graveyard simultaneously activates Hardened Academic, whose triggered ability places a +1/+1 counter on the Kelpie; state-based actions see the opposing +1/+1 and -1/+1 counters annihilate each other, leaving the Kelpie clean and ready to be sacrificed all over again.