Grim Poppet | Progenitor Mimic | Hapatra, Vizier of Poisons

Cards

All permanents on the battlefield (
Grim Poppet with a -1/-1 counter on it and
Progenitor Mimic as a copy of
Grim Poppet and with toughness 2 or greater).

Activate
Grim Poppet by removing a -1/-1 counter from it, putting a -1/-1 counter on
Progenitor Mimic.
Hapatra triggers, creating a creature token.
Activate
Progenitor Mimic by removing a -1/-1 counter from it, putting a -1/-1 counter on
Grim Poppet.
Hapatra triggers, creating a creature token.
Repeat.

This combo has been estimated to be Exhibition (Bracket 1+).