({20} magic symbol) minus ({1} magic symbol) for each creature and artifact you control each turn available.
Steps
Activate
Spark Double using
Avatar Kuruk's ability by paying ({20} magic symbol) minus ({1} magic symbol) for each creature and/or artifact you can tap while activating it, causing you to take an extra turn after this one.
Declare
The Neutrinos as an attacker, triggering its ability, blinking
Spark Double. Choose to have it enter the battlefield as a copy of