An inanimate object
Personification is used in literature to make something boring leap out at the reader so they can imagine the object themselves.
This of course isn’t needed if the object is already alive, the only similar thing you can do there is zoomorphism (making someone seem like an animal).
So in answer to your question, personify anything inanimate, and if you want the best effect on the reader then definitely do use personification.
A good example of personification is something like ‘the whispering wind’, as wind can’t actually whisper.