Source Imaginary, as the name itself and the movie cover visually explain you get the idea, a girl who has an imaginary friend who most likely talks to her through a teddy bear. This could be a movie idea

Imaginary is an American supernatural horror film directed and produced by Jeff Wadlow and written by Wadlow, Greg Erb, and Jason Oremland. The film stars DeWanda Wise, Tom Payne, Taegen Burns, Pyper Braun,