Cartoon movie with smoke creeping out of a door.
There is this movie I vaguely remember from when I was younger, and it keeps popping up in my mind over the years. There is a young kid who sees a parade, I think she might have some sort of a pet? Then at night a big ballon comes and takes her to this fairytale/fantasy/forest even? The part that I really remember though is there is a black smoke that leaks out of a door- a villain like thing. Maybe there was even a key that opened it when it was not to be used. However it is the smoke that creeps out of the door that sticks out in my mind. Please help it has been bothering me a long time.