Use stream of consciousness to answer the following. Stefan Karl Stefansson (/ stfn stfnsn /; Icelandic: ( stfaun khartl stfaunsn); 10 July 1975 -- 21 August 2018 ) was an Icelandic actor and singer, best known for playing antagonist Robbie Rotten on the children's television series LazyTown.

Answer this question based on the passage: when did the guy who played robbie rotten die?
The important part for answering this question is: Stefan Karl Stefansson (/ stfn stfnsn /; Icelandic: ( stfaun khartl stfaunsn); 10 July 1975 -- 21 August 2018 ) was an Icelandic actor and singer, best known for playing antagonist Robbie Rotten on the children's television series LazyTown. Final answer: 21 August 2018.