Always on the beat.
Back Scratcher backpack is a Rare Fortnite Backpack from the Neo Ninja set. This back bling is currently unreleased. It's an upcoming backbling that have been leaked but hasn't been put on sale in the Fortnite Item Shop yet! Back bling Back Scratcher is reactive. It means it changes or evolves (reacts) depending on certain things in game (damage dealt to opponents, if it's day or night...)
The set Neo Ninja contains 2 cosmetic items.
The backbling Back Scratcher belongs to Chapter 2 Season 2. This backbling is a leaked backbling, an upcoming item that will release in the Fortnite Battle Royale game. Therefore, you cannot buy it yet at the Fortnite Shop or get it by any other method.