Bringing a brand-new fast-food item into the world is anything but an exact science. You can do all the planning, field testing, and marketing in the world, but at the end of the day, theres no way to know whether a new release will sell until its unleashed on the public.
And few fast-food chains have rolled out as many failed menu items as McDonalds.
McDonalds is the largest burger chain in America, and also the one under the most scrutiny. When it rolls out a new menu item, its usually met with a huge amount of fanfare as well as a major push to make sure that as many folks as possible are aware of it. So when an item fails, it fails spectacularly and embarrassingly.
Though McDonalds has a set menu at most of its places, the chain is continuously testing out new items, usually in a handful of local marketplaces, in order to try to get an idea of how theyd fare nationally. Many items, like the BBQ Chicken, Corn Dog McNuggets, and Catfish Sandwich, never constructed it past the local testing phase, and some items, like the infamous McLobster roll, are still available regionally.
Some items were tested out seasonally to see how they fared as well, never to return once the season ended. International McDonalds has become even more adventurous, with some genuinely outrageous creations attaining it to menus, also meeting with various high levels of success.