The website says copyright 2006 but that looks like a pre-'06 model (grille, headlights, wheel wells.) Maybe some of our Japanese friends on the forum can help us out with what is special about this option/version and the T4Runner model release history?
That, sir, is a fender-mounted mirror that helps avoid "blind spots" when driving. In Japan, their cars are right-hand-drive (since they drive on the left side of the road). The left side of the SUV in the photo is the 'passenger' side over there, so that odd-looking mirror helps the driver to avoid side-swiping somebody (a pedestrian or another vehicle) which might be in his blind spot.
If you ever went to Japan, you would find that it is very, very congested -- at least compared to the USA. Their roads also are usually smaller and narrower than ours. Many more people crowded into much less territory. {Look at the video of their 'pushers' who work for their subway system. They get paid to cram people into train cars so that they can get the sliding doors to close. They even wear white gloves while doing it!}
Look at some other JDM (Japanese Domestic Market) cars and you'll see quite a few of those funny mirrors.
I wouldn't be surprised to see more than a few of those lying on the side of the road after getting accidentally clipped...
Edit: I just watched the opening video on that site, and got a better look - it doesn't stick out as far as I thought. It still looks oddly non-symmetrical...