Watch Beware the Slenderman (2016) HD Full Movie Free on solarmovie.do. Watch Beware the Slenderman (2016) online free. Tells the story of two 12-year old girls, who attempted to murder one of their friends in an attempt...Tells the story of two 12-year old girls, who attempted to murder one of their friends in an attempt to appease Slenderman, a fictional monster from a horror website.