Grim Poppet + Hapatra, Vizier of Poisons + Vesuvan Shapeshifter

Grim Poppet

Hapatra, Vizier of Poisons

Vesuvan Shapeshifter

How it works

1. Activate Grim Poppet by removing a -1/-1 counter from it, putting a -1/-1 counter on Vesuvan Shapeshifter.
2. Hapatra triggers, creating a creature token.
3. Activate Vesuvan Shapeshifter by removing a -1/-1 counter from it, putting a -1/-1 counter on Grim Poppet.
4. Hapatra triggers, creating a creature token.
5. Repeat.

This clever loop relies on a clever bit of identity-swapping to continuously recycle -1/-1 counters between Grim Poppet and a clone. By casting Vesuvan Shapeshifter and having it enter as a copy of Grim Poppet, you create a mirror image that also possesses the original's counter-moving ability. You can then spend Grim Poppet's activation to strip a counter and place it onto the Shapeshifter, which triggers Hapatra, Vizier of Poisons to spawn a deathtouch Snake token. Immediately after, you use the Shapeshifter's own copied ability to move that counter right back onto Grim Poppet, triggering Hapatra yet again to flood the board with infinite creature tokens and enter-the-battlefield triggers.