Psycho Driller is one of the four skins released under the Rise of the Mechanos part of the Mechanos offer. It could be individually purchased using game coins in late June 2017.
Psycho Driller could be purchased in the Skins Shop under the ‘Mechanos’ tab for 3320 coins. It was available for a limited time and may not be available for purchase in the future.
Details of this offer can vary depending on location, platform or time.
Note: The Rise of the Mechanos offer with the Psycho Driller skin was released again for a limited time in late June 2018. The price for Psycho Driller remained the same at 3320 coins.