From my research i found black goo satan's Achilles Heel to be our very moon!(which was called the medusa/satan's head by our ancestors).(see also the saying "to kill a snake you destroy its head!")

Also an ex mossad agent on a youtube video i saw long time ago revealed according to him "the only way" you can kill a beast and any beast and that is by cutting its food source.

Which means if we all humans were to stop reproducing and find also a way to make all lifeforms on this planet unable to reproduce that would be another way of killing the beast/black goo hydra/satan.

That's my 2 solutions of killing the black goo and as you see both are extremelly hard to acomplish.

There might be also a 3rd solution and that is "NOT LETTING THE BLACK GOO SATAN FOOLING HUMANITY INTO FIGHTING ITS ENEMY FROM SPACE! WHICH ARE THE GALACTIC POLICE/ANTIBODIES OF THE UNIVERSAL ORGANISM WITH MISSION TRACKING DOWN GALACTIC DISEASES LIKE THE BLACK GOO AND EXTERMINATE THEM!"

About how black goo satan plans on fooling us into fighting his star war, check this thread!
Thread: Be Warned! The Elite is Preparing a Staged Alien Invasion to Provoke an Interstellar War! Don't Become Fools!