Burger King is firing up a kooky deal for customers today that will leave them saying, “Cara Mia.” To celebrate the release of its limited-edition menu featuring items inspired by “The Addams Family,” the fast-food chain is running a buy-one, get-one-free deal on Whoppers for one day only. More specifically, rewards members can get a free Wednesday Whopper, aka a classic Whopper served on a purple bun. Here’s everything you need to know to score the spooky deal. The deal is only valid on Oct. 17, just in time for the October supermoon Participating U.S. Burger King locations will offer a “BOGO Wednesday’s Whopper” deal to rewards members on Thursday, Oct. 17, which just happens to be the day when an October supermoon will reach peak fullness. The offer, aptly marketed as Uncle Fester’s Full Moon Feast, is valid while supplies last, and purple buns aren’t guaranteed. You have to buy one full-priced Whopper to score the deal The limited-edition collection features four items inspired by the animated film “The Addams Family.” (Burger King) Rewards members who purchase one Wednesday’s Whopper at regular price on Oct. 17 will get another for free. The limited-edition menu item is basically a traditional Whopper, but served on a purple bun that gets its color from purple potatoes. Certain exclusions apply The BOGO deal is only valid on the Burger King app and website for order ahead or dine-in. Rewards members can use the six-digit “My Code” located in their rewards account (where available) and activate the offer in the “Offers” tab to score the deal. As always, price and participation can vary and upsizes/modifications can cost extra. Rewards members are limited to one offer per account and the deal can’t be combined with other coupons or offers. Lastly, the offer isn’t valid in Alaska, Hawaii and U.S. territories, and it isn’t available during breakfast hours. The new Addams Family menu features four items Each of the items in the limited-edition menu are inspired by the animated film “The Addams Family.” Wednesday’s Whopper: A Whopper with Swiss cheese, tomatoes, lettuce, mayonnaise, ketchup, pickles and onions on a purple bun. Thing’s Rings: Crispy onion rings with themed packaging. Gomez’s Churro Fries: Crispy, fried churros covered in cinnamon sugar and served with chocolate dipping sauce. Morticia’s Kooky Chocolate Shake: A shake made with soft serve, chocolate cake batter fudge, and black and purple cookie pieces. Burger King also has a limited-edition collection of King Jr. Meal toys to celebrate the new menu. This story first appeared on TODAY.com. More from TODAY: 57 things to do this Halloween that are frightfully fun 84 Halloween trivia questions and answers that are a real treat What are ‘boo baskets’? Parents debate this love-or-hate Halloween tradition This story uses functionality that may not work in our app. Click here to open the story in your web browser.