This is reflection or lense flare. You'll notice the "horse shape" doesn't move untill the camera does. Changing the angle of reflection. At
points you even see movement within the shape of the horse that mirrors the flickering of the fire so i think the fire is the source.
In the Japan videos, the "horseman" seems to be pixelated at a different resolution from the rest of the shot - implying to me that it's digitally
added to the video later. So, I'm calling this one "hoax". Somebody just want's this to be true so badly, that they couldn't wait for the real
thing.
If the Egyptian footage is a reflection, why does the crowd appear to react to it? One guy with a white jacket jumps away and runs as it appears, and
the crowd divides as the apparition rides through. Unless all of those people are in on the Hoax...it isn't a hoax.