That wasn't one of the specials, kiddo. (Via)
The photobomb is so pervasive online, there should be a separate Internet set aside just for their viewing. They come in all varieties, but they are not all alike. There's the low-level, intentional "I'm gonna eff up your pic with my dumb face" photobomb. There's the dichotomous photobomb, where the foreground and background are at direct odds with each other, but this usually involves little more than someone in the background happily living life who just happens to not fit into the intended foreground pose.
Then, occasionally, there's something magical. A photo that captures a moment in the background that might have been lost forever had the people in the foreground not demanded their own smiley mugs be recorded for posterity. This sort of photobomb is what shatters our self-imposed boundaries, sending us journeying outside of our own narcissism to the outer ends of life's rich tapestry, where it just so happens some little kid just applied a death grip to a busy waiter's balls.
This photobomb is life. It's happening, and it's glorious.