Symbiote Ellie Phantom AU
After she was saved from Destabilization, Ellie gained a nifty new power. She can Melt on command and move around freely, which is just a really fun power, even if she is a bit weaker when she uses it .
But one day, she gets really badly hurt. Like, Really Hurt. Let's say the GIW got a lucky shot and managed to capture her, and experimented on her for a week before she managed to escape.
She can't keep her Human Form stable anymore, but her Goop Form is good enough for now. All she needs to do is find an Ectoplasm Rich Environment and try to heal up the best she can. Hopefully Danny will find her after she misses her monthly Visit.
She ends up in Gotham while searching for a place to heal, but the GIW is hot on her tail.
She needs a place to hide, and the only way she can think of is to overshadow somebody and pretend to be them while the GIW passes her by.
So she jumps into the nearest person she can find, a girl close to her age jumping across Rooftops.
But since she was in her weaker Goop Form, she can't enter a person without their permission. So she slides up to the person in Goop Form, jumps on her Back, and telepathically asks her for help, begging for permission to hide in her for a bit.
The girl she tried to overshadow was Cassandra Cain.
After some begging, Cass agrees and Ellie sinks into her. Again, she can't fully Overshadow her, so she's basically a passenger until Cass decides to give her some control.
The GIW passes by them, and Ellie tries to leave Cass only to realize that she can't. Since Cass was exposed to the Lazarus Pits, she is has a weird Biology, and since Ellie already had a Wierd Biology being a Halfa Clone as a Pile of Goop, they somehow can't leave eachother.
Cass gets a new Roommate, but instead of sharing an apartment, its her body. It's honestly not that bad, Ellie can give her some of her old powers and she can still communicate by making a Goop Head come out of Cass's shoulder.
They get along really well too, Ellie can ways be there for Cass whenever she needs somebody to talk to, and Cass is the Supportive Older Sister who helps Ellie talk about her feelings.
The Bat Fam also doesn't know. They figure that this will probably be fixed soon enough, so there's no real reason to tell her Family. They do find out after a few weeks however.
Cass accidently uses Ellie's powers in front of one of her brothers, which causes them to tell Bat's which means the entire family knows by the end of the day.
Cass has to explain the situation and introduces her new little sister. "This is Ellie. She's a Meta who escapes a secret Government Organization and asked for my help to hide from them by hiding in my Body. Unfortunately, we can't split up because her powers reacted strangely to the Lazarus in my blood. She is now my sister. You are not going to make her leave, I will not let you."
It takes a while, but the Bat Fam ends up accepting her. They do end up looking into that "Secret Government Organization" though, and find that they have been experiencing Raids by an army of Ghosts for the last few weeks.
"Oh right, I missed my monthly visit to my brother." Says Ellie from Cass's shoulder. "He must be looking for me, no biggie."
It's definitely a Biggie.
You know, I can make this weirder by taking something else from the symbiotes: their reproductive habits.
So the idea is that after they find Danny and convince him to stop his one man war (So the justice league can do their jobs), they start looking into why Ellie is latched on to Cass more specifically. Eventually, after some oddly suspicious symptoms show up, they find that Ellie did sucessfully start regrowing her body. As a embryo.
Now Cass gets to deal with being a pregnant teenage crime-fighting superhero / ballerina with a reincarnating half ghost clone child (Who is very vocal and active through the process) and a overstressed half ghost teenage superhero gene donor who is trying to help out with this whole kerfuffle, but can always find a way to make things worse.
Oh Ho!! This would be perfect for a Cass/Danny ship!
Danny: “We always joked that you were technically my daughter, but it was weird that you were physically two years younger than me. I guess now it wouldn’t be as weird.”
Cass: “Co-parents?”
The press would go nuts!
“Is that a baby bump showing on Cass Wayne?! And who is this mysterious young man who showed up? Is that the baby daddy?!”
Danny would become an over protective menace. Cass would constantly be talking him down from murder to protect them.
Cass: No murder!
Danny: But he hurt you!
Cass: No murder! You can't protect me from jail!
Danny:... Good point. Maiming it is!
Cass is such a good partner. She doesn’t need Danny to protect her, but she lets him do it anyway because it makes him feel better.
Cass thinks it's cute. And it does make it easier to keep him calm if he feels useful. Plus pregnancy? Stressful as fuck. She's happy to outsource some of that so she can rest. Who knew growing a whole human was such a high intensity activity!
Alfred. That's who. He takes Danny in hand as well. Puts those instincts to good work.
Alfred: Master Danny. Come with me to the kitchen. You should learn to cook. It will help you keep Miss Cass healthy.
Danny of course is RIGHT THERE. Takes every lesson in the kitchen with the same seriousness as a Bat does fighting. Learns all of Cass's favourites. Puddings, tea. Anything. Alfred is very smug about it all. Cass is eternally thankful to have some time to herself. Not that she hates the hovering. It's cute. But it is a bit much.
Had a thought. Danny absolutely summons Frostbite to get trained in ghost healing. Frostbite of course is thrilled to teach. And even more pleased to know the Great One's mirror child will be given the chance to be truly healthy soon!
Frostbite happily gives check ups to Cass, showing Danny how to do it. And then Danny has an idea. Ghost are empaths right? Is there a way for him to share the pain with Cass? For when she is having Ellie? Or a ghost way to make it easier for her?
Maybe it's just MY Ace projecting? But like? Free baby without having to sex? Nice(tm).
And you KNOW Ellie was all "!!!!! OH SHIT!" Etc at first? Like? She was ABSOLUTELY cool with stay a symbiote? Finding a way to separate and taking shots like she'd always done for the rest of time.
Bodily autonomy and consent are HUGE for the Phantoms. They are GHOSTS and furthermore, Ellie is a clone. He whole creation was Vlad stealing Danny's choices and then watching her brothers MELT.
Cass has been nothing but loving and super cool about all this! And now her Weird Ghostie Goo Powers and whatever the fuck a "Lazarus" is, are combining to high jack Cass' body to make her a BABY FACTORY!? OH HELL NO! Get rid of it!
She was probably hysterical. Nearly crying. A big ball of guilt and self loathing and distress.
And Cass? Is just quietly considering things. Ellie is right. It IS her body. And while she's calming Ellie down? She's thinking about what SHE wants.
Poor Bruce learning about the horrors of ectoplasm. It does NOT help that "Oh, Cass HAS Ecto. Just not enough ya know?" I'm sorry. My daughter has corrosive badness in her? How? Everyone in my family does? How? What do you mean we aren't baseline humans anymore! Even Tim? How?
Focus on the fact you're getting a grandchild Bruce. Focus on the baby! Focus on the fact the baby will have Martian like powers. .. And we are back to anxiety. Alfred! I need Xanax!
And yeah. It will be a great way to explore self perception. And relationships. And family bonds, how they form. How they are chosen. It's gonna be great!
Danny is going to be even more over protective than Bruce. Who is gonna see if and be like... Am I that bad? Is this how others see me? Oh no. I think I get the teasing about my back up plans now. Excellent! I have an Ally in this fight to keep my idiot children alive!
Bruce casually just speed running the “Am I that bad?” to obtaining an ally in planning fast enough to give everyone witnessing it some degree of whiplash.
I can just imagine Bruce, Danny, and possibly Tim working on so many (too many) contingency plans. Just collectively thinking up any and all risks and then how to handle those risks. Is this unhealthy? According to Alfred, yes. Will they continue? What Alfred doesn’t know (he knows, they know he knows, they’re just pretending that he doesn’t know) won’t hurt him.
Also, the crisis over ectoplasm is great. Bruce is gonna learn everything he can about how that affects everyone after that info bomb is dumped on him. He doesn’t want to be caught unawares like that again, especially with something that could hurt any of his kids (and soon-to-be grandkid).
Bruce and Danny on an increasing paranoia binge creating back ups for their back ups? Cass and Alfred just sigh and grab an idiot each.
The Justice League have to be warned about their tendencies. Danny won't prepare for self defence. But give him someone else he needs to protect? Oh boy.... (Oddly enough once he learned about the threat of Joker, the clown disappeared How strange)
Bruce: Jason, I can't believe you weaponised Danny like that!
Jason: .... Don't know what you mean B? What did he do?
Bruce: The Joker has gone missing!
Jason: Well. That sounds more like a blessing to be honest B. And anyway. Are we SURE it's another ploy of the clowns anyway??
Frostbite gets summoned over to help create a proper 'guide to care and feeding of halfas and liminals'. Frostbite is pleased Danny and Ellie are with a GOOD family now! Yes he CAN help with all the other liminals with icky ecto!
I'm happy to see how far you've taken my little addition to the idea. Let's add something else. All that ectoenergy which would start flowing within Cass during the symbiosis would have some consequence. Is it dragged out during birth, or does it remain within her? Does it turn some of her talents into powers? Like Bodyreading into empathy, stealth into invisibility, or Acrobatics into flight? And how does those powers affect the pregnancy?
So Cass becomes a Halfa due to the pregnancy? Interesting idea!





















