It pierced through the ceiling of the mall but soon after impact the comet broke apart releasing a fine purple dust. Said dust soon spread throughout the mall, carried by the force of impact and the HVAC system. At first, people were concerned with the impact itself and anyone who might have been killed (zero) or wounded (about five people, but nothing more serious than a sprained ankle and some minor cuts, scrapes and bruises) and property damage. It would take some time before the first changes started to really manifest and when they did, they had already begun to spread.
The exact nature of the changes was baffling and exactly why this was the case was never fully put down. Some said it had to do with the comic store and toy store at ground zero. Regardless, the effects soon manifested. The infected would change into various anthropomorphic animals with multicoloured fur. In general they were reckoned to be quite attractive with slim athletic builds, with aging reversing to the twenties. But for all that, they'd also become androgynous. Men would usually slim out, women would loose their breasts and everyone would loose their nipples. Most notably all sexual organs would soon be reabsorbed. Not that the transformed minded the loss as the transformation carried a change in attitude and identity which wiped out conceptions of "male" and "female".
These physical changes came with mental ones as well, though they retained their intelligence and much of their personalities. The transformed would find the changes to be pleasurable and whatever worries and fears they had at the prospect of the loss of their sex soon faded away, as they would come to identify as non-binary. At the same time they also developed a high desire for intimacy, with a strong desire towards hugging, cuddling, petting, nuzzling and similar and a degree of stimulation from these activities which they found more than made up for the lack of sex. Finally, most would develop a strong drive to spread the virus to uninfected humans so they'd share in what they had.
The era of men and women had past. The time of the genderless anthros had come.