Odd is one of the four skins released under the Party part of the Agar.io Birthday offer. It was available for purchase in mid July 2017.
Odd could be purchased for $4.99 as part of the Regular Pack. This pack also included the Funky skin and either 3250 coins (Browser) or 700 DNA (Mobile). Odd was not available for individual purchase and may not be available for purchase in the future.
Details of this offer may vary depending on location and platform.