Behemoth is one of the three skins released under the Beat the Zilla Killa part of the Jungle Quest offer. It could be individually purchased with game coins in March 2017.
Behemoth could be purchased in the Skins Shop under the ‘Jungle’ tab for 2900 coins. This skin was available for a limited time and may not be available for purchase in the future.
Details of this skin can vary depending on location, platform or time.
Note: The Beat the Zilla Killa sub-offer with the Behemoth skin was released again for a limited time in early February 2019. The price for the Behemoth remained the same at 2900 coins.