https://www.gamespot.com/articles/fortnite-halloween-costumes-and-more-coming-to-ret/1100-6460681/

This was inevitable: Fortnite Halloween costumes are on the way. Retailers Spirit Halloween and Spencer's have completed a deal  with Epic Games for "a range of officially licensed" Fortnite costumes, as well as accessories and gear based on the brand. 

The available items on Spirit Halloween and Spencer's websites include adult and children's costumes based on skins such as the Black Knight, Crackshot, Dark Voyager, Skull Trooper, and Cuddle Team Leader. You can also purchase basic, rainbow smash, and party animal pickaxes, as well as a light-up boogie bomb that also plays sound.