Gustaf Caspar Orm Skarsgård (born 12 November 1980) is a Swedish actor. He is known for his roles in Evil (2003), The Way Back (2010), Kon-Tiki (2012), and Oppenheimer (2023). He also appeared in the HBO TV series Westworld (2018), as Merlin in the Netflix TV series Cursed (2020), and as Floki in the History Channel series Vikings (2013–2020).