Stuff like Inside Mari (by Shuzo Oshimi), recursion (by Blake Crouch),Sibs by F. Paul Wilson. I love the identity horror of the genre and am frustrated that the idea is mainly only used for comedies or family movies. I want to find more books with those themes of loss of identity and being trapped within someone else. It’s terrifying either having someone else in control of you or completely losing your identity and having to live as someone else
by Misfit_t0y