Back to the ankle bracelet thing, it probably would be like the perfect storm kind of thing. If Danny hadn't been in his ghost form when they put it on, it wouldn't affect him that much. Not just talking about his health but also his powers. He wouldn't be able to transform but his core would have adapted to give him small bursts of power when he needed them. On that note, he wouldn't have let them place anything on him if he weren't so confident of his powered half and its untouchability. Sure, they waited until he was asleep and it was after they caught him running around town lost. Specifically near Ivy's preferred park, since she seemed liminal enough to hide him, which would've been a good plan if it weren't for the small blooms of blood blossoms she had growing in one of the corners. One that Danny hadn't noticed until it was too late and he was close enough to it to get poisoned. Extra effect, considering he didn't have his alive half helping his core fight back against it.
So already weakened, poisoned, in Ghost form, and a little too cocky about the dimension not having anti-ghost tech, and he ends up with a cuff that weakens his core enough that it's struggling to keep him alive, let alone give him access to his powers. It would have probably been fine, for his relative health anyway, if it hadn't been for the blood blossoms already poisoning him and the fact that his core kept trying to push them out with all its strength and kept falling slightly short each time, weakening him more and more, taking away the energy he would need to turn back to his other form.
Skipping to him living with the bats, he would not be passive about it. Not if he'd tried to saw his leg off in hopes that it would help him get rid of the cuff. As that would have been a last resort, he would have first tried lock-picking it. It had not gone great. Meta cuffs usually account for that and won't come off with a normal key, much less with a lockpick, no matter how skilled Danny was with it. It would have probably been fine but well, Danny's luck rarely works in his favor. Desperation had made him move a little too fast and, when he heard a click (the false release mechanism specifically installed for those situations), he had gotten a little too excited and had tried to rip the cuff off his foot.
Not only did it not work but it made it malfunction in the worst possible way. It still blocked access to his core, more strictly now that it knew he was a flight risk and had tried to remove it without the key (protocol for criminals but I doubt they'd have a different one to use on kids they consider misbehaving, especially if they're already set on restraining them to that extent, which gross but yeah). But now it also started giving him shocks of increasing frequency and potency. Danny did not do well with electricity. Not since the portal. It strained his already tired core even more. Danny kept trying. Nothing worked. His jailors were a little too good at keeping him captive. Danny never stood a chance.
It would have still been fine, or like survivable. Danny's core was strong. Danny had experienced unmentionable horrors and still been able to go back to his life without being too affected by his trauma (no, Jazz, him not talking about it isn't a defense mechanism of repression, he's just vibing, ok?). He could've probably bounced back from the nightmare his life had become since the cuff. He would have taken a Vlad rescue at this point. But he was also in a new dimension with minimal access to ambient ecto (in this dimension, all the extra went directly to the Lazarus pits and was immediately contaminated by Ra's continued existence) and not enough access to his core to turn emotions into energy. All of it focusing on cutting the blood blossom and now enduring being continually electrocuted, which the bats somehow still did not notice...
It was only a matter of time. Maybe he could've lasted longer. Maybe he would've if he had gotten any sign, however small, that there was hope his torture would come to an end. There was nothing. No green notes appearing or size-changing dogs showing up to play. No gav or other Fenton related vehicles or communication devices making their way through the new dimension. No ectoplasm to absorb. Not even the ability to detect if it existed unless it was right in front of him, very close.
He had had a brief moment of hope when Jason had come to visit the manor the first time. He was highly liminal, his ecto was contaminated but still present. Maybe Danny could communicate with him through ghost speak despite it. He tried. Nothing. He tried again. Not even a twitch. Apparently the underdeveloped core wasn't able to catch much. Jason had left shortly after, feeling wildly uncomfortable –like a pebble had been stuck on his shoe but somehow feeling it on the inside of his stomach,– without really being able to know the reason (he felt Danny's desperation and attempts of communication but didn't know what it was).
It was the last drop for Danny. He let his core go (ghosts are deeply driven by emotions, Danny giving up wouldn't be enough to kill him usually, even without access to his human side, but with a core that's barely hanging on? Yeah. That was enough). He felt another tiny sliver of hope when he felt his powers returning to him as his core gave up but it was short-lived. As soon as it started to restart, Danny felt the infernal cuff starting his torture again. He only had enough time to tell the closest person his last words: "you killed me", before he completely faded.
The torture didn't end there. Of course it wouldn't. Danny could never be so lucky. It continued when his senses returned to him as his body started rotting and his core went back to frantically trying to cure him, still completely unable to do anything about it. Or even talk. It went on as he felt every single cut. Every part of the dissection (did it count as vivisection if Danny was aware enough to feel every second of it? Danny thought it did). Every time they stuck their hands inside of him and moved his organs around. Every time they decided to cut one out and put it on the side, separate from his body but somehow still connected to his core and therefore still cognizant of each time they cut them into pieces to analyze and see if that has been the cause of death.
They didn't touch the vines left by the blood blossoms poisoning. Of course they wouldn't. Apparently they thought that was his core's weak attempt at healing instead of a parasite leeching off the little energy he had access to. They didn't remove the cuff either. Danny would've probably recovered if they had done either. Of course, that meant it didn't even occur to them. Even after he was dead they wouldn't grant him his freedom.
Danny didn't think he could ever forgive them. He had experience with ambivalent feelings towards people. After all, his parents had loved one half of him while threatening to tear the other apart molecule by molecule. He knew how to compartmentalize. He refused to do that with them. Sure, they had been friendly enough and "nice" to him. They had also kept him captive and tortured him continuously with their ignorance, going so far as to keep going even when he no longer had a say in it. Of course they wouldn't let him rest in peace even when they thought he was fully dead. Even when he had gone as far as spelling it out for them that they had been the cause. His opinion never mattered to them to begin with so why would they start now that he wasn't able to communicate it anymore.
So Danny was not surprised. Disappointed, sure. Annoyed. Frustrated. Tempted to go all ghost king on their dimension and blacklist it from the Infinite Realms (not that he would, he acknowledged that most of the people in it shouldn't suffer for the choices of the few, it was still tempting). Not surprised. So Danny endured. It's what he did best. What he had been doing ever since the accident with the portal. Maybe even before that. It's not like he had a choice. Not as long as that cuff stayed connected to his core. Not when the blood blossoms were still there. Still alive. Still in effect. Keeping him a little more dead every time and making it harder for his core to make a come back somehow. Danny was low-key rooting on them to succeed. He just wanted it to end. Even the GIW would have been more tolerable than this. He still couldn't do anything.
He got a small reprieve when they decided to cut his core loose off his body. He hoped they would leave it alone for a while, just enough for it to recover a little bit of its strength. Enough so Danny could leave or at least turn it invisible and intangible until they gave up searching. He didn't have that kind of luck. They inserted it into another body. An incomplete one his core would have to work hard to heal. One that wouldn't give him a reprieve at all, even when it wasn't his. Even when he shouldn't have had to heal it just because it was forcefully connected to his core. Danny was perfectly capable of going without a body and having his core create a new one. It was actually better for him. Not that his opinion had ever mattered to them.
At least breathing didn't hurt that much anymore. Aside from the emptiness, it was the best he had felt since his encounter with the blood blossoms. Maybe even before. He could feel his strength returning to him and his core kick-starting his heart. He gave himself a moment to hope that it would be enough to get out of this nightmare dimension and back to at least the Infinite Realms. Frostbite would surely know how to help him.
The hope didn't last long. After all, the cuff was still there, ever present on the same ankle as his previous body. Of course it was. He wasn't sure if he preferred it when the blood blossoms were still in his system. At least they limited the time he would have to endure existing in this state. Now, with a still diminished core and new organs to regrow, because apparently they couldn't even do him the kindness of putting him in a complete body, he would be just as vulnerable before, except without the impending final death to look forward to. Just enough work to keep his core strained and busy so he still couldn't access his powers and a certainty that he wouldn't even be able to escape them with death.
He hoped Jazz got there soon. He wasn't sure even his sister would be able to get him out of this. He hoped she stayed far away from them. He didn't want her to be exposed to these monsters and didn't want to know what they would do to her. Either way, it wasn't up to him at all. He still couldn't communicate with them. Not that they'd listen even if he did.
And the cuff stayed on. Danny pretended to sleep. It didn't work for long. Maybe next time he'd be the one to cut himself open and cut his core loose. Surely that would get rid of the restrictions. If he timed it well. He could probably get away with hiding it somewhere in the house with them none the wiser.
Also what do you mean the foster kid you were keeping dies, his last words being 'you killed me' and your first thought is 'ah yeah, let's do an unofficial autopsy when we clearly have no clue of what's going on to see what killed him. Couldn't have been us' like no, don't cut open the child just because, especially when Danny probably had vivisection PTSD. That's so rude (and unfortunately kind of on beans for the bats in this situation)
Unrelated, did you know tumblr has a 30 tag limit? I sure didn't. On that note, writing this while on mobile was kind of a nightmare and whenever I started a new paragraph (or edited one in) it went back to the beginning of the post.