Good movie, might watch again, but hard to recommend.
This is a weird movie. Not only do you get a stop motion like imaginary monkey as a character, you get Brendan Fraser acting like he thinks it acts, an other-world for the dead and imaginary alike as well as Whoopie Goldberg as Death. Oh, and Dave Foley naked.
The story itself, an imaginary character taking over its creator's body for some nefarious purpose, is actually really good. The execution just isn't fantastic the entire time, particularly the 3rd act. When a movie starts good and ends weak, it leaves you with a poor memory of it.
Ultimately, it was an enjoyable, but it could have been a lot better, and there are plenty of better movies to watch.