Something with a core body swapping element and substantial plot/rating. Not purely fluff and no plot kinda stories. BL and modern day stories only pls.
https://www.novelupdates.com/series/reborn-into-a-hamster-for-233-days/ MC becomes hamster but later gets his own body back https://www.novelupdates.com/series/warhead-pet-hamster/ MC’s sole gets into experimental hamster’s body