Humans.
To the ears of God, they were nothing but ants for his amusements. WERE.
Now, the Humans become a race of upstarts that destroy the perfect balance that God have tried so hard to create and keep, and Humans also become a big pain in the back. So Good decided to go full out nuclear, sending a Monster to kill and slaughter the Human Race. The monster he send is truly a monster, destroying the entire North American continent within a month, and proceed to Europe a day later. No Human weapon, including the Atomic Bomb, can destroy the monster.
Mankind begged the God for help. God initially refused, until the people swore to never destroy the balance of nature again. God saw his creature is destroying the balance as well, so God agreed. They sealed the creature, and bring it to another world.
The creature will remember this, and vow to kill God and Mankind with it.
In another world.