I only remember the trailer and vaguely at that. It began with a statistic about how many people go missing every year and are not found. There was an "at first they thought people were being abducted by aliens, but what if the problem was already on earth" part. The visual part I remember was an astronaut looking down a bathtub drain with a flashlight. Dude sees nothing, turns to leave when a single large black tentacle comes up and grabs him, pulling him down. The color scheme of everything was a light-dark contrast. Whites and blacks, that odd gold/brown light fading into black.
I'm guessing late 90's, maybe early 2000's. Probably a scifi horror deal, and I'd actually like to see it since the trailer's been in my head so long.