Watch Slender Man (2018) HD Full Movie Free on SolarMovie. Watch Slender Man (2018) online free. In a small town in Massachusetts, a group of friends, fascinated by the internet lore of the Slender...In a small town in Massachusetts, a group of friends, fascinated by the internet lore of the Slender Man, attempt to prove that he doesn't actually exist - until one of them mysteriously goes missing.