The great Fur Flood.

What came before.
Millions of years before mankind, there existed animals (no shit) And they lived in peace until one particular animal came to existence....MAN.

Man were a bunch of horny fucking assholes. Man decided to systematically make every animal on earth fuck each other, each offspring mating with the next species until they ended up with the penultimate lifeform, when it came time for man to fuck the Ulti-beast. The resulting cum explosion created the greatest plague the world has ever seen. Furries.

What must never cum come again.
A splinter cell group of furries have vowed to once again create the ulti-beast and use genetic modification to make it even stronger than before, once the beast has been created the furries will attempt to fuck it and probably end the world or some shit.