The gods’ ultimate decision would be determined by way of lottery raffle. Three words would be drawn from a hat, and those three words would determine their path. In the end, those three words wound up being “fat”, “Cerberus”, and “babes”.
“How utterly ridiculous,” one said, “Only a perverted fool would go through with this idea! It’s disgusting! Depraved! Deviant! Degenerate! ... Let’s put it into motion right away!”
So the terms of the virus were deliberated and decided upon through a series of debates. First they debated on the word “babes”. Surely they couldn’t turn them all female, for with no seed they would surely die out. Unless... they made it so that the infected could reproduce via parthenogenesis, that is, the females could produce unfertilized egg cells along with polar cells that are discharged during their climax with their partner, usually when they're scissoring. The combined body heat would stimulate the polar cells to fertilize the egg cells, resulting in an embryo. Given that they're canine beings, the Cerberuses would give birth to litters of pups, going from one up to six. One other god thought this could lead to a rising overpopulation, even more numerous than the current humans, so they proposed a solution: make it so as there's a 30/70 chance their copulation could result in pregnancies, and only if they were copulating in a particular way, scissoring.
The other gods reached a consensus over the two ideas, and moved on to the word “fat”. Obesity came with a myriad of horrible health problems, which none of them wished to deal with. Thus, they decided that their virus would eliminate most of these problems wholesale, such as heart disease, diabetes, sleep apnea, and anything else considered “not fun”. The gods then deliberated on the final word remaining, “Cerberus”. Surely they couldn’t turn the humans into feral animals, much less a mythical one. Anthropomorphism was quickly agreed upon for the fulfillment of the requirements.
In the end, the gods decided that the virus would transform the infected humans into overweight anthropomorphic three-headed canine creatures. They would all be female and use female pronouns, and they would all have conventionally beautiful faces, and each head would have a different personality with the middle head being the one in charge, the Ego, and the other two being the Id and the Super-ego. The average weight would range between 450 pounds and 600 pounds, though it could climb higher depending on the individual, and they would have bottomless appetites to match their new girth. Their heights would also increase, with an average Cerberus standing 7ft tall, and it was also decided that the virus would affect both dogs and humans, and would be transmitted through both saliva and sexual fluids.
Their work finished, they sent the virus to Earth, sat back, and waited.