Taken from his wife Steinunn's facebook page:
"July 10, 1975 – August 21, 2018
My beloved, Stefan Karl Stefansson, 43, has passed away after battling aggressive bile duct cancer for two years. Per Stefan's wishes, there will be no funeral. His earthly remains will be scattered in secrecy in a distant ocean. Stefan's family wants to express their gratitude for the support and warmth received in recent years, and to express their deepest sympathy to the many friends and fans of Stefan Karl."
May the man that played Robbie Rotten for almost 20 years forever be in our memories and in our hearts.