Posted by Mr. Q at 6:00 AM Friday, March 1, 2013
Patents. You could file for a utility patent if you have created something functional -- like this strange creeping doll. But you could not get a utility patent if the only thing that is novel about your plush doll is its appearance (though you could seek a design patent). After March 16, you cannot obtain patent protection if you have sold or publicly disclosed, or published information about your invention any time before you filed your patent application (except if the actual inventor-applicant created the publication and it was made up to one year before the filing date). Doll companies weigh the time and expense it takes to get a patent (two years and several thousand dollars) versus the short shelf-life of many dolls, and typically do not pursue patent protection unless there is novel technology or functionality. It's usually not a cost-effective strategy.
Trademarks. You can register a trademark for the name of the doll or you may be able to acquire trademark rights for the doll's appearance (if it is particularly distinctive), as well. Protecting trademark rights are part of every doll company's strategy. However. you can't obtain a trademark registration until you have begun selling the dolls (though you can file an application reserving your rights).
Copyright. You didn't mention copyright law which has been one of the most cost-effective types of protection for doll companies. (It certainly helped Cabbage Patch Kids and the Bratz.) Once you create the doll, you automatically receive a copyright. You can register that copyright relatively quickly (within a few months) and inexpensively ($35 to $65 depending on whether you choose paper or plastic).