Mad Fragment is one of the two skins released in the first part of the Ark Raider's Mystical Shop offer. It could be purchased as part of an item deal in mid September 2018.
Mad Fragment could be purchased for $7.99 in the limited time "Best Deal!" which included 25000 coins, 1200 DNA and the Ancient Relic skin. This skin was not available for individual purchase and may not be available for purchase in the future.
Details of this skin may vary depending on location, platform or time.
Note: The first part of the Ark Raider's Mystical Shop offer was released again for a limited time in early April 2020. The included items and amounts for Mad Fragment remained the same. However, the price increased to $9.99 on mobile while remaining at $7.99 on browser.