Plague is one of the two skins released in the fifth part of the Mr. Spank's Beats Shop offer. It could be purchased as part of an item deal in late February 2020.
Plague could be purchased for $9.99 in the limited time "Best Deal!" which included 20000 coins, 1200 DNA and the Doll House 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.