Grim Poppet | Spark Double | Nest of Scarabs

Cards

All permanents on the battlefield (
Grim Poppet with a -1/-1 counter on it and
Spark Double 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
Spark Double.
Nest of Scarabs triggers, creating a creature token.
Activate
Spark Double by removing a -1/-1 counter from it, putting a -1/-1 counter on
Grim Poppet.
Nest of Scarabs triggers, creating a creature token.
Repeat.