If watching the movie made it clear to someone "skilled in the art" how to make and use the invention then the people behind the movie are the inventors, not you. You can only patent what you invent.
If the item in the movie was a sci-fi impossibility, like a skyhook or a hyper-drive and you have figured out a way to actually make it then you have invented something and can patent it. No one will successfully sue you merely for getting a patent on something you truly invented. Getting a patent itself does not infringe someone else's rights; making a product is what potentially infringes someone else's rights.
Having a patent means you can (try to) exclude others from making it; a patent grant does not give you any particular right to make/sell what you have patented. For example, someone might have a patent that covers a sub-component of your product or it might not be legal - like some weapons systems. If you make a product and name it the name given in the movie, that might infringe some trademark or other right the movie producers think they own.
And, at least in the U.S., a toy can be patented.