[se] caught up in something

When you see something out of the corner of your eye, turn to look, and see nothing at all, what should you conclude? That you were having a hallucination? Or that your peripheral vision is perhaps not to be trusted. Ask yourself, are you tired? Drunk? Under the influence of something? Is the lighting good? Are there lots of moving shadows about? Are there reasons you have to think that your mind is playing tricks on you?

Because...well, because it would be absurd to think that out of the corner of your eye you had just seen a house. A house with a figure slamming its hands against one of the upper windows with enough force to shatter it, and then...

Well, then you looked and it was gone.

Nah, you're probably just tired.