the action of spoiling a photograph by unexpectedly appearing in the camera's field of view as the picture is taken, typically as a prank or practical joke

the concept of photobombing has probably been around as long as photography

spoil a photograph of (a person or thing) by unexpectedly appearing in the camera's field of view as the picture is taken, typically as a prank or practical joke

we were interrupted and photobombed by at least twenty tourists