Steam Skull is one of the three skins released in the fourth part of the Mad Gears Shop offer. It could be purchased as part of an item deal in late January 2020.
Steam Skull could be purchased for $14.99 in a limited time deal which included 25000 coins and 1800 DNA. 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 fourth part of the Mad Gears Shop offer was released again for a limited time in mid March 2021. The included items and price for Steam Skull remained the same for this release.