TSF Monogatari

After a terminal diagnosis, Takumi Musashino agrees to experimental gene therapy and gets more than he bargained for — the treatment works, technically, but comes with a side effect nobody warned him about: he wakes up as a girl. Not metaphorically. Full body transformation, new face, new everything. Now she has to figure out who she is while navigating a high school that's suddenly very interested in her for all the wrong reasons. Some classmates, like Anri, step up and actually try to help her adjust. Others... not so much. The male classmates especially start treating her like she's become a completely different person, which in some ways she has, and in others, absolutely hasn't. That tension — between who Takumi was and who she's expected to be now — is where the show lives. It's a 2-episode OVA from 2011, so don't go in expecting a slow burn character study with room to breathe. It moves fast and leans into its hentai genre, but the gender identity thread running through it gives it more weight than you might expect from the premise. If you've watched Kashimashi: Girl Meets Girl or thought Ranma ½ needed a more grounded emotional core, this scratches a similar itch. It's not a masterpiece, but for two episodes, it's doing more with the transformation premise than it probably gets credit for.