With the size of the second mutation outbreak, the authorities increased their efforts in trying to find the organization that stole the mutation liquid and was spreading it. To help them, they hired people who had become mutants in the last two outbreaks, mainly because they were no longer at risk of being infected or infecting anyone else.
Cory, Yara, and Cindy, who had gotten used to the body they'd shared for a few months now, were working with the security team hired by a summer club. Some normal people had some prejudice towards them for being mutants, as they seemed to believe that she would just fuck anyone near her when she felt like it, even though they explained many times that after the disinfection treatment they no longer feel the urge to fuck anyone. Even though after the mutation they started to feel a little uncomfortable wearing clothes, they still dressed in personalized clothes when they went somewhere, especially with a lot of normal people, and so they wore the company's uniform. As they were part dogs, their employers instructed them to use their keen sense of smell to find anyone who might be carrying the mutation liquid and thus prevent a possible new outbreak.
The anthro cerberus girls didn't know exactly what the mutation liquid smelled like, so they were always suspicious of people they smelled some unknown scent on. This attitude proved correct when they saw a normal girl pass by them and a smell strange to them came from the girl, who was only wearing a bikini and didn't seem to be taking anything with her. They followed the girl without her noticing.
The mystery girl was walking between the tables when she reached inside her bikini bottom and, judging by her finger movements, pulled out a sealed vial containing a purple liquid from inside her vagina. She broke the seal, stopped behind a waitress and was about to mix the liquid into a soup she was going to deliver when Cory, Yara and Cindy announced their presence and ordered her to stop. The waitress then realized the girl behind her and what she was doing, which made her get away from the girl and ended up dropping the tray she was carrying, which fell upside down causing all the dishes she was going to deliver to be lost.
The Cerberus girls chased after the mysterious girl, who weren't as fast as they were but was treacherous, so much so that Cindy radioed for backup. During the chase, one of the their bachups recognized the mysterious girl, saying that her name was Wanda and she was the daughter of the owner of the club.
Eventually Wanda was cornered, but before they captured her she turned the glass containing pure mutation liquid into her mouth and drank it all.
Not knowing exactly what was to come, but knowing the proportions that the situation could reach, Cory, Yara and Cindy immediately ordered the evacuation of all normal people from the club in order to avoid a new outbreak. Then they were left to deal with Wanda, as they were already mutants and would be immune to a new infection.
"Why are you doing this Wanda? You're going to cause your dad a lot of trouble with this." Cindy said
"I don't care what my dad or you guys think. This world is so boring with so many normal people, I just want to do my part to make it more interesting." Wanda said as her mutation started and she was already getting taller, her muscles getting more defined and fur covering her entire body.
Wanda said as her mutation started and she was already getting taller, her muscles getting more defined and fur covering her entire body. With the change of her head she had already fully transformed into an anthro tigress, but the transformation wasn't over yet. Her head split in two, a second pair of arms grew just below the original one, her originally C-cup breasts almost tripled in size while three more pairs grew below them and her navel became a pussy. To top it off a pair of feline cocks grew between her legs, accompanied by a ballsack containing four testicles hanging just below that replaced her original vagina.
"That's exactly what I wanted. I've never felt so strong, I'm ready to spread the mutation." Wanda said and tried to run after the people evacuating the club.
Cory, Yara and Cindy ran to stop her and managed to reach Wanda, but the two-headed tigress girl was much stronger than them and immobilized them on the ground.
"Since you want it so much, I'll make you my first victims." Wanda said and ripped the conjoined dog girls uniform and stuck her dicks in two of the pussies, which were the ones that belonged to Cory and Cindy,
The three friends had learned well by this time that they were conjoined that both for their pussies and for their dicks, even though each one felt them all, they had a specific owner since one of each was more sensitive to one of the bodymates than the others. They then decided to let themselves be fucked to buy time, since being mutants nothing would happen to them.
In a short time, Wanda came and filled the inside of them as much as possible with her first load of cum. She then walked away and stared at the girls with a mischievous smile.
Cory, Yara and Cindy, when they felt something strange in their body, tried to get up but couldn't stand up, and soon after they noticed all six of their hands turning into paws. They realized what was happening, but it was strange because they were already mutants and should not go through a new mutation. They then looked at Wanda in amazement.
Wanda laughed and said "You are surprised, right? What I took was not the normal Mutation Liquid but its improved version that the organization created, Mutation Liquid X. With that same one who is already mutated, he can be infected again and undergo a new mutation. It is worth mentioning that as we didn't want to, we never researched a treatment to stop the infection, but I can say that the method for the normal version of mutation liquid is useless against it. The only ones immune to Mutation Liquid X are those who have already been transformed by Mutation Liquid X."
The conjoined friends were stunned by the revelation as their transformation proceeded, with their anthro dog body having become fully animal, except for their breasts which remained unchanged. Then their entire body grew proportionately until they were ten feet tall while on all eights (the quadruped position but with six front legs). The tips of their dicks then swelled and there formed heads, which they found to be exactly the same as theirs were when they were still normal girls, giving each of them two fields of vision temporarily. The transformation was completed with the eyes and ears of the canine heads between their shoulders closing as the tops inflated into ballsacks, and the muzzles with the closed mouths became dicks. The new cocks between her eyes were upside down according to their normal placement, with the ballsacks resting on top of them.
With Cory, Yara, and Cindy's transformation complete, they found themselves feeling the urge to infect others again, which they hadn't since their time in quarantine, but they were managing to resist. They then turned to Wanda, advancing on her. Their new size had given them more strength and speed, which allowed them to overpower the tigress girl easily this time.