One possible plot could be that Black Cat is on a heist in a place where Dr. Octavius also has an interest. His tentacles might squeeze her as a way to stop her from getting to a valuable item first. This could lead to a power struggle between them where Black Cat uses her agility and thieving skills to try and escape the grip of the tentacles.
She could get injured. The tentacles are strong, and if they squeeze too hard, Black Cat might end up with broken bones or bruises.
One possible plot development could be that Kagome is in a state of shock and fear at first. But then she might start to fight back using her spiritual powers. She could try to purify the tentacles, causing Naraku pain and making him loosen his grip.
In this fanfiction, it could be that Kari is exploring an ancient, cursed place. As she ventures deeper, black tentacles emerge from the shadows and start grabbing at her. These tentacles might be a manifestation of the curse. Kari's journey could then be about finding the source of the curse and breaking it to stop the tentacles from attacking her. She might meet other characters along the way who either help or hinder her progress.
One possible plot could be that Kairi is in a strange and dangerous realm where the black tentacles belong to some sort of dark entity. She has to use her courage and any latent powers she has to try and break free. Maybe she discovers that the tentacles are being controlled by an old enemy who she must then defeat in order to escape.
One possible plot could be that Mary Jane gets caught in a dangerous situation where Venom's black tentacles are being controlled by an evil force. Maybe she's lured into a dark alley and the tentacles suddenly wrap around her, restraining her movement. She then has to use her wits to try and escape or call for help.
Well, the plot could involve them getting married in an alternate universe where the rules of their relationship are different. For example, in this universe, heroes and villains are more likely to form alliances through marriage. So they get married, but then face challenges from other villains who don't like Black Cat being on Spiderman's side, and they have to fight together to protect their new relationship.
I'm not sure specifically as I haven't read that particular fanfiction. But generally, it might be about a character named Juvia who is struggling while in a situation involving black tentacles. It could be a story full of challenges, perhaps in a dark or mysterious setting.
Perhaps in this fanfiction, the Black Cat has a personal vendetta against Spider - Man that has been brewing for a long time. Maybe she blames him for something that happened to a loved one. So she decides to take matters into her own hands and kill him. This could lead to a series of intense battles and chases as Spider - Man tries to figure out why she's after him and how to stop her without hurting her too much.
Well, the plot could involve the cat - Harry Potter - stumbling into the Black Butler world. Maybe he's lost his human form due to some dark magic. He could then encounter Sebastian and Ciel. The cat - Harry - might use his magic in cat form to help or hinder the duo in their investigations. For example, he could use his invisibility ability (in cat form) to spy on enemies.
Well, it could start with Black Cat stealing something important just to get Spiderman's attention. When Spiderman catches up to her, instead of fighting, she reveals her true feelings. Spiderman, taken aback, is initially hesitant but then gives in to the moment and they kiss. This kiss could then set off a chain of events where they have to deal with the consequences of their new relationship, like how it affects their respective reputations in the city.