Bill was no fool when it came to the manner of workings his kind was capable of, but he paid attention to his own business and didn't bother with the business of others. Pick a section of the multiverse, and stick to your own lane, that was how he operated. In the eternity he'd existed, though, he could admit he hadn't seen EVERYTHING. He told Gideon he knew LOTS of things. Not ALL things. He liked surprises. It made eternal existence more bearable.
This was one of those things he didn't know, but now did.
Naturally, possessing Filbrick's body would have side-effects aside from the physical cues of his eyes. He had been in the man's body a full year before he fathered the twins, and now the full realization hit him as he felt his own essence coming from both Mabel and Stanford.
Filbrick's body hadn't just fathered the twins. HE had fathered the twins too.
It all made sense now.
Stanford's obsession with the weird—hell, probably his sixth fingers in general!—his ambition, his sociopathic mindset, his capacity for mental manipulation.
Stanley's natural tendency to con and lie, his unnatural ability to control his own Mindscape.
Dipper's cold, vindictive streak, having no problem with handling magic, his craving for answers to questions that haven't been asked yet.
Mabel's absolute comfort with weirdness, her psychopathic way of thinking, her ability to charm anyone, and her literally endless imagination that went above and beyond what children were capable of.
He had given a part of himself into the twins, and in facto to his third child Sherman, and it had completely escaped him.
Bill contemplated between the bubble and the gold figure, wondering to himself why he didn't sense this when he was in Stanford or Stanley's minds, or Dipper's body. Could there have been a trigger for it? He reached out and touched the bubble, feeling a pulse run through it before it doubled back at him like an echo. The sign of the Shooting Star cracked even further, and the chains creaked in protest. In his hand, the golden statue's energy shuddered, and Bill actually SAW the micro-movement shift again.
Of course. These prisons that he had put Mabel and Stanford in were concentrations of his own power working directly into the energy that was threaded into their DNA and soul strings, increasing the amount of energy they were able to utilize of their own will.
These weren't just prisons. He had put them into incubators.
This changed everything.
Bill quickly scrapped the plan of having Dipper find the bubble and trap himself in the 'prison'. Having TWO of his own kind in this one incubator could be catastrophic, and not in the good, fun way.
He displaced Stanford's figure and placed his hands on the bubble, manipulating the energy around it to displace and absorb into his own form, as much as he could, in any case. Already, Mabel was gathering and manipulating her OWN energy, fueling her Mindscape's power at a rate that was concerning. He managed to shrink the bubble down to a decent size, then held out one hand, summoning Ford's figure back to him before encasing it in a bubble of its own, sealed in with the sign of the Six-Fingered Hand.
Inside the bubble, the gold reformed back to organic components, and Bill quickly willed the man inside to sleep. This bubble too was an incubator instead of a prison, but Stanford's affinity was for external mental power, rather than internal like Mabel's. The incubation process would be slower if he was asleep.
Bill teleported to his personal space at the topmost part of the Fearamid, setting the bubbles down in the air before sitting back to think about his current predicament. There were several ways this could pan out. He could destroy Mabel and Stanford while they were still in the bubbles. That would not be hard when they were unconscious. He could then seek out and destroy Dipper and Stanley before they had a chance to incubate and become an actual threat.
Then again, this rare anomaly of four hybrids of his own kind WAS almost too good to pass up. He had been earnest in his offer to Stanford in joining him; the man was just far too sore for his own good. But perhaps Bill could appeal to the insatiable craving for the unknown in him…
Bringing Stanley over to his side would actually be easier…the world had not been kind to the younger of the elder pair, and as long as the younger pair of twins were safe, he'd be game for most anything.
Mabel was already the furthest along in the incubation process. Give her the eternal summer she always wanted, and her own demonic nature would take over her human need to care about HOW the rest of the world would pan out.
Dipper was another story. His Pine Tree was definitely a once-bitten-twice-shy type, and would be the hardest to convince. Perhaps he'd save the boy for last; if the rest of the Pines clan were a part of all this, Dipper would follow once he saw there was no other option besides death.
Bill's eye glowed brightly, honing in on every surface of Gravity Falls to locate the barest trace of his inherited energy. After a few moments, he could see Dipper hiding out in an abandoned store, hunkered down under a table in the corner. Stanley had discovered Stanford's secret bunker and was armed to the teeth, having already killed the Shapeshifter that had gotten free, as well as several other beasts.
He closed his eye and snapped his fingers, summoning several henchbats to him and with a flicker of his will, giving them the sight of where the two other Pines members were. "Find them and bring them to me unharmed!" he commanded. "Engage en mass for the old man, he'll take as many of you down as he can."
The henchbats were sent off, leaving Bill alone again with the two incubating Pines. He tented his fingertips, contemplating for a moment before turning to Stanford's bubble, summoning it to him and popping it.
Stanford hovered mid-air, jerking awake with gasping and coughing, curling up on himself as he felt a sensation akin to electric sludge running through his body. It was mildly painful and incredibly uncomfortable, making him feel all sorts of wrong.
"Well well well, Sleeping Fordsy finally wakes up."
Ford's eyes flickered upward at Bill, his body shaking with terror and rage, and Bill could see a golden glow behind Stanford's eyes and a slight darkening of skin on his hands. Bringing Stanford out mid-incubation was probably agonizing, but best to work this out now, while the man was on the fence about things.
He reclined back, holding the curled-up man in his palm. "Bet you're feeling weird, eh, Sixer?" he asked conversationally. "Like your insides are rearranging, your mind taking in too much, your skin crawling…that's gotta be uncomfortable, amirite?"
"W…what…..did you…d…do…?" Ford demanded, his voice shaking violently as he curled up tighter, looking closer to being ill.
"Something unprecedented," he admitted. "Didn't really MEAN to, but I'm a guy who rolls with the flow, y'know? It's a LONG, extensive story, so it's best if I just SHOW you."
"S…show me…? What—" Stanford was cut off when Bill poked a clawed fingertip to his head, filling his mind with EVERYTHING from the beginning, from possessing Filbrick to getting the Rift from Mabel. It happened in an instant, and Ford collapsed in Bill's palm, shaking violently.
"Wow, your mind is durable!" Bill commented, leaning back. "When I did that to Filbrick, he had a stroke. Must be your demon side working out for you, eh?"
Ford shook harder, feeling tears leak out of his eyes, absently aware that the fluid wasn't clear, but was instead a transparent, sooty black. "…N…no…" he stammered, curling up tighter. "Th…that isn't….h…how c-could you…?"
"Oh, but it IS, Sixer," Bill said, lifting his hand closer. "Didn't know it would happen, but it did. You, your twin, and your little niece and nephew carry MY lineage. Your family are Ciphers as much as they are Pines! And THAT'S where your little secondary demonic puberty thing is coming in.
"See, my kind doesn't breed the same way YOURS does. We're creatures of energy, incubated until we're ready to be 'born', so to speak. Energy is contained in incubators until we gather enough sentience to structure ourselves into forms. Like so." He gestured to himself. "It's a little detail I overlooked, but possessing the body of Filbrick Pines had me dispersing my own energy into his genetic coding, passing it on to you, Stanley, and Sherman."
He laughed, leaning his hand on one side of his body. "You were totally right in telling Pine Tree that Gravity Falls is a magnet for things that are special. But, Mister Arrogance, that doesn't JUST include you and him. Fez and Shooting Star are just as special, since THEY carry my lineage too."
Bill shifted his hand so Ford would face Mabel's bubble.
Ford's body ran cold, the squirming of his insides clenching tighter. He could see flickering energy sparking around the bubble, sense a shifting of SOMETHING inside. There was but a shadow to be seen from the outside, but Ford could see it was starting to resemble something other than a 12-year-old girl. "…Mabel…"
"She's progressing nicely," Bill said. "Surprisingly nicely. I always liked Shooting Star. She's chaotic, she appreciates discord, and thrives in pandemonium. When she's done incubating, she'll be a force to reckon with." His eye shifted to Stanford. "…Much more of a force than you could hope to contend with. And you thought SHE was the one suffocating Pine Tree!"
"N…no…" Ford murmured, feeling more transparent liquid run from his eyes. "Didn't….m-mean it like that…!"
"Don't kid yourself, Fordsy, we both know you picked your favorite and ran with him," Bill laughed. "You drove my little Shooting Star into the woods, and had her put the Rift right in my hands. But past is past, and now it's time to focus on the future." His eye flickered red. "YOUR future. HER future. You have two choices, Stanford. With a simple flick of my wrist, I can set you two on fire until you're ashes, ridding you from being a problem once and for all…"
Bill internally smiled when he felt the panic rise up in Ford's emotions, seeing the man's hand twitch out toward Mabel's bubble. "OR," he continued, lifting Ford at eye level, "I can finish the incubation process. You'll be changed for the better, as new members of this world, with your family. Fez and Pine Tree included."
Ford's expression flickered rapidly between fear, apprehension, concern, contemplation. Bill decided to nudge a little further.
"You'll be a creature of infinite possibility, Stanford," he crooned. "All the time in the universe to study the mysteries of the universe, to gain infinite knowledge, to watch new creations and knowledge forge up from galaxies yet to be born. And you wouldn't have to sacrifice anything for it. You'll have your soul, your family, and even me supporting you the whole time. So what's it gonna be, Sixer? Death, or eternal existence with everything you could ever want?"
Ford bit his lip until it bled, taking only moments to weigh his options before sighing, his body deflating in resignation. If not for himself—tempting and succulent the prize was—then for Mabel's life. He owed the girl that much.
"…I'll do it," he said. "Please…..PLEASE…just…promise me…"
"Your family will have the same choice as you," Bill assured. "Trust me, them joining me will be FAR more entertaining than me killing them. I'm curious as to what abomination you'll all turn out to be! GIDDY, almost!" He lifted his hand, Ford's body levitating in the air. "Have a nice sleep, Stanford. See you soon."
He put Stanford to sleep, then encased him back into the bubble, sealing it with the Six-Fingered Hand before putting it up next to Mabel's.
He wasn't lying. He actually COULDN'T wait to see what manner of nightmarish monsters his lineage would be like. He just needed to bring in Fez and Pine Tree...