Grim Poppet + Nest of Scarabs + Omni-Changeling

Grim Poppet

Nest of Scarabs

Omni-Changeling

How it works

1. Activate Grim Poppet by removing a -1/-1 counter from it, putting a -1/-1 counter on Omni-Changeling.
2. Nest of Scarabs triggers, creating a creature token.
3. Activate Omni-Changeling by removing a -1/-1 counter from it, putting a -1/-1 counter on Grim Poppet.
4. Nest of Scarabs triggers, creating a creature token.
5. Repeat.