When the movie came out, it was a bit of a sensation. It was a real genre juggernaut. I remember the poster, and being annoyed by the poster. “Insidious is.” I -S, Is in red in the middle of the title. I remember seeing the trailer. Boy, did they make liberal use of that “Insidious is.” Fashioning it into the marketing tagline to beat all marketing taglines, “Insidious is… insidious.” Which in fact, it kind of is, because it has a way of insidiously making you feel like maybe you've seen it before. And that might give you a false sense of security or complacency, until it expertly subverts or exceeds your expectations, terrifying you. But its claws are sharp and getting sharper, and they get under your skin. Because it is a little self-referential and it's a lot genre-referential.