“It” and “It: Chapter 2” have been described as the most terrifying movies of a generation, which is an impressive feat, considering they come from source material that’s nearly 40 years old. And since this isn’t even the first adaptation of King’s source material, we’re left to wonder why this scary story is so affecting. Star James McAvoy might have some insights on the matter, as his dream life was terrifyingly altered after rereading the novel to prepare for the role. The actor has some important things to say about why so many people relate to the dark tale. This is how It: Chapter Two changed James McAvoy forever.