Rabid is one of the four skins released under the Party part of the Agar.io Birthday offer. It was available for purchase for a limited time in late July 2017.
Rabid could be purchased for $9.99 as part of the Birthday Pack. This pack also included the Delighted skin and either 7000 coins and a Mass Boost (3X, 24H) on Browser or 1800 DNA and a Birthday Potion on Mobile. Rabid was not available for individual purchase and may not be available for purchase in the future.
Details of this skin can vary depending on location, platform or time.
Note: Rabid was released again for a limited time as part of the All the Internet Things offer in mid November 2019. This time Rabid could be purchased individually for 3200 coins.