Zelz was originally created through the Slug Co.'s theft of the everlasting gobstopper recipe, but Zelz and Tobi never really had their first brush with each other outside of the factory being besieged by Zelz walking through the C4's home factory terminator-style.
After that, Zelz was badly damaged and had to spend time regenerating his body through sucrose vampirism.
Simultaneously, this was also when the Factory got itself the special space-rift room tech that they had needed to repel such an advanced threat, Sen working overtime to rebuild the damage done to the Factory and build the current bubble of temporal rooms; created through Llyfy's creation and employed by Sen's devising.
During that time was when Abby and Tobi were both out in the field securing the money and tech that needed to fund this project.
This was also when both of them decided they enjoyed the outside world and fell into their own individual vices.
Tobi thought he was immortal and grew cocky, sure that nothing could hurt him. He enjoyed people enjoying him, and could power through most Black Widow and Honeypot traps unharmed.
Abby grew her social network, trading favors for people and growing ingrained in the more unscrupulous side of society, advertising her skills at smuggling things inside her body as a valuable asset on the black market.

Now, talking about the Black Market of New Illinois, there is a certain highly illegal substance that would become the MO for a certain criminal organization as an alternate to the classic Black Ski Mask when they employ their methods of bank robbery. This drug of the day's name is Toon Dust. This powdered dilution of Toon Ink transforms the imbiber into an anthropomorphic Toon version of themselves for around an hour, so long as they aren't standing in the ink-saturated land of Little Toontown.
Abby unwittingly supplied them their contraband, though the hammer of consequences hasn't fallen on her just yet as the police scramble to try and catch the slippery tooned crooks using their toon abilities to evade the law.

As Abby started her business in the underworld, Tobi started his in the limelight as an adult model and a rather pious sort of do-gooder, learning to read and recognize predatory practices taking advantage of unsuspecting people, going in himself, beating them at their own con and taking their score. Black Widows, Roofie users and Honeypot traps all learned of him rather quickly, though not before Tobi managed to make a tidy profit cleaning up their cons out from under them.

Eventually, Zelz recuperates and tries again to get back into the factory. However, Sen is waiting for him and has prepared well. Every time that Zelz manages to destroy another room, the resources for that room are simply restructured and molecularly appropriated back onto the conveyor-belt of dimensional pockets that Sen's creation churns out, crystallizing back into identical rooms for Zelz to struggle through, again and again and again.
Through a combination of weariness of his own body's deterioration and the mental strain of going through identical room after identical room with seemingly no end in sight succeeds in repelling Zelz.
Though in that failure, he has one other lead of information to hunt down; namely the two individuals who remain outside the protective bubble of the factory.

Zelz succeeds in getting to Tobi.

Tobi was so busy making money doing photoshoots that he didn't notice the shady, dangerous themes creeping in. He was glad that the credits were pouring in and never stopped to think of the implications of using his body so. Why would he? He was essentially indestructible, after all.
Zelz paid for an unwitting Tobi to undergo sexdoll transformation. Once he was immobile and helpless to resist him, he then stepped in, paid the photographer that did the actual deed and then proceeded to drain Tobi in the shady offsite photoshoot area in order to bolster his own decaying metabolism. Succeeding with his mission, Zelz falls back to experiment with the pure sugars he drained out of Tobi's body.

After Abby finds and retrieves Tobi's body, the C4 family because of this incident would eventually culminate Artificial Soul research, to preserve the soul if a case of their own artificial bodies failing and would eventually manage to retrieve Tobi's soul out of his body that Zelz drained.

Tobi then in spite of being trapped and drained, becomes obsessed and fascinated with the idea of souls and of immobility, of utilizing his body to more dangerous extremes; proving on some level that he and Zelz are more alike than anyone wants to admit.

Though that is a story for another time.
After seeing her brother being immobilized and weakened, clinging to his soul in a shell of rubbery latex, Abby is spurred to desperate action.
She dug deeper into the underworld, hearing whispers of a "Shadowy Supreme Supervillain Supplier" and immediately vowed to give such people a wide berth if she could help it.
Soon, she found herself sprinting as fast as her paws could take her away from a giant hulking shark-man chasing her through the warehouse as she adjusted the wooden crate she'd inserted up her vagina walls, now sloshing back and forth through her gelatenous soda syrup as she ran through the warehouse, dodging past musclebound thugs trying to stop her.
The crate sloshed and oftentimes bowed when she ducked around or through the legs of a grunting wall of muscle trying to retrieve the crate that she'd stolen from them, though the shark seemed to be the only one truly pursuing the chase while the others coralled her away from any doors leading to freedom. She recognized that she was getting penned in and that only drove her to panic.
Looking to her right, seeing goons. Looking to her left, seeing goons pumping their fists and starting the chant, "Sam. A. El! Sam! A! El! SAM! A! EL!!"
To which the giant hulk of a shark produced an old-style boombox and punched the play button with his sausage of an index finger.
The thudding bass of their signature blend of Predarap thudded through the warehouse, making the windows bow and flex. Though to the soda labrador that it was targeted at, it felt like her liquid core was being vibrated apart by the musical shockwave. She screamed, falling to her knees as her body swelled, the Predarap surging her mind larger, telling it to grow and thicken.

Samael looking impressed as the growing labrador clenches, her voice deepening as her tomboyish huffs and groans turn bassy and husky, the thieving bitch before him clenching as she rolls onto her side, her increasingly muscular squeezing together powerfully as her gooey tension flexes for the first time; accidentally crushing the crate of product between her gooey thighs. Her plastic PVC shell was ripping under the pressure, letting gooey drips of her inner body to sag out of the tears in her soda container, large bulges that looked suspiciously like muscle glorped outwards as the Predarap did its work in transforming her rapidly into a hulking bodybuilding meathead just like the rest of the warehouse.

The shark's toothy predatory grin turned into a frown as he looked at the labrador, then back down at the crushed crate of product floating inside of her shell. "You owe me for dat." He snarled, snapping his teeth at Abby as he twisted the dial of the boombox up to eleven.
Abby on the other hand was only trying to roll onto her side out of the trajectory of the boombox's subwoofers. "Urgh, my fakkin head... turn that shit off!!"
Still gritting her teeth and succeeding in rolling over, her ripped shell was hanging off of her like a fashion mistake of a tube top, squeezing her around the waist.
Abby lashes out with her foot, the wobbly jello-like force kicking Samael square in the gut and sending him crashing into the Predarap boombox, splitting it in two.
Abby realizes that she doesn't quite have control over her cohesion in this form yet.

The shark stands up, grunting with irritation and concentrates, the air around his body forming into armored plates. “You wanna fight? I’ll give you a fight.” He growls, gnashing his teeth, before lashing out at the gooey goliath with a chop, intending to slice her midriff in half. “That was my favorite boombox you broke."
Samael steps carefully around the ruptured bags of Toon Dust that are spilled out on the floor of the warehouse as he twists his body, crossing his chest to his fist in a powerful cross, intending to glance across the vest of the bulging hound, to use the magic of his his wind plating to slice and dice.
But instead of severing her in two and freeing the product like he'd hoped, his attack splits through the middle of her plastic shell- which when severed, sends her midriff explosively sproinging outwards, catching the shark in the chin as her gooey midsection explodes outwards from the pinched pressure barely holding it in by Abby's ruined shell!
Abby grimaces, the feeling rather unpleasant as she scoops up the remaining bags of product into her larger goliath body and makes a break for it, not sticking around to fight in an unfamiliar body, even though her head is telling her to stay and fight.
She makes a baseball slide down into the side of the street, her gooey form flowing with practiced ease down the concrete storm drain and into the sewers along with the still-intact bags of product.

Down in the sewers, most of the errant Toon Dust trying to mix with her body coagulate inside of her, Abby starting to turn as the ink fights with her body for dominance. What ends up happening is that the Ink dilutes itself within her, turning her into a temporary sort of half-toon as she makes a mad dash through the sewers; her head filled with Predarap and her body filled with Toon Ink.
The sewer grate clangs viciously as Samael throws it aside, dropping into the sewers to rush after her, the slick surface proving no obstacle as he goes after the disoriented and conflicted creature, now simply wanting revenge for such a vigorously fucked up shipment. Da boss ain’t gonna be happy about this, so now he just wants to punch down. Samael thinks he's lost her for a second, but Abby then stumbles over him as she staggers around the corner. He punches at her and his fist slams into her body, causing her to wobble upwards for a moment and then sag back down on top of him.
The confined piping of the sewers clings at the edges of Abby's body as she lays down on top of the shark, the sewer water touching his gills feels positively rank and the concentrated cocktail of Abby's own body isn't much better.

Samael starts viciously punching her, attempting to flip her into the sewer water and let her get diluted and melted. It would be good enough, to put an end to this mess. Unfortunately, his constant frantic hammering up at her prevents her from finding a proper foothold in the sewer muck and as much as she tries to roll off of him, she can't for his struggling. All of this while she desperately tries to figure out why this feels so hilarious to her while simultaneously being so infuriating to her street cred that she hadn't known about until a second ago.
Samael growls. “You fuckin’ bitch, you fucked up my whole job! I’m gonna fuckin’ kill you!"
Abby cackles like a jackal, dipping her own gooey hands between her ripped chest and pushing down on Samael's shoulders, worming her way through his air armor. The toon ink is already starting to coalesce past Samael's body, and he can feel it. He's been warned about the side effects of this stuff, and he saw the bitch go down into a puddle of it... even as angry as he is, he knows that keeping in contact with the doped up hound can't be good.
Especially now that she's snarling madly between chortles and trying to dunk his head down into the shallows of the dank sewer water.

Samael made a supreme effort and jerked his legs up, attempting to flip the giggling monster over his head and into the sludge behind him.
His legs push up into her body. It almost feels as though he's trying to kick up against mud.
Finally, she sticks her fist over his gills, her eyes dilating into slits as she tries to force her gooey fingers up under his neck-slits, sawing her gooey digits against the rim of his gills.
The feeling of ink and acidic soda mixed with sewer water grating against his secondary breathing apparatus is... unpleasant to say the least.
Samael gasps in sickness and anger at the feel of the disgusting substance, finally deciding that retreat is the greater part of valor and slips away from Abby’s grasp, into the sludgy water behind him. It was horrible, but WildClawz had good disinfecting showers.
Abby does little more than collapse into the sewer water, letting the next tide carry her away into the disinfection plant, all the while cackling madly and slamming her fists into the ground of the concrete sewer, finally able to dilute herself in the plant's chemical compounds.
The process is largely unpleasant as it whitewashes and bleaches her soda, leaving her weak and thin, with only one bag of Toon Dust in her possession as she staggers home, thin, weak and drained of sugar.
Samael arrived home, smelly and probably infected by something horrible, and lacking both his boombox and his freight and wondering what the fuck he’d just run into.
The only real event is the distillery, now saturated with mass quantities of Toon Ink and soda.
The next week is spent trying to quarantine and discern the origin point of the Toon Labrador outbreak that would later go on to spearhead the police's already aggressive War on Toons.