The 'assassination classroom tentacles' in fanfiction can be quite a unique and often strange concept. Some might see it as a creative way to explore the strange and otherworldly elements of the 'assassination classroom' universe. However, it also might be considered a bit out - there and not in line with the more mainstream interpretations of the series.
One way to incorporate 'assassination classroom tentacles' into non - sexual fanfiction is to use them as a form of defense mechanism for the characters. For example, the tentacles could be a new ability that a character discovers and uses to protect themselves or their classmates from danger in the classroom.
One possible fanfiction could be about Nagisa, as a girl, having to deal with the unique challenges in the Assassination Classroom. Maybe she uses her newfound femininity to her advantage in different assassination attempts. For example, she could play on the stereotypes that others might have of a girl being less of a threat, only to surprise her opponents.
One possible fanfiction could be about female Karma's journey in the Assassination Classroom. Maybe she uses her intelligence and unique skills to outwit the other students in various assassination attempts. For example, she could come up with creative plans to get close to Koro - sensei while still maintaining her cool and mysterious demeanor.
One characteristic is the exploration of the unique characters. Fanfictions often dig deeper into the backstories and personalities of the students and the teacher in 'Assassination Classroom'. For example, they might expand on how Nagisa came to be so calm and observant. Another aspect is the different plot twists. Some fanfictions create alternate scenarios where the assassination attempts take on new forms or have different outcomes.
She could have a secret power that only she discovers over time. For instance, the power to read Koro - sensei's thoughts briefly when she makes direct eye contact with him. This would give her an edge in the assassination attempts. She could then use this power to set up elaborate traps based on what she learns from his thoughts.