Oculus
The Oculus is a mysterious black, spherical object that floats above the northern Pacific Ocean on Gallerra. Located at a latitude of 31° 30′ 13″ and a longitude of -168° 23′ 54″, the Oculus never strays from this position, though it does rotate about its center. It remains perpetually floating about eight meters above sea level—low enough that during storms it is not uncommon for the tops of the waves to wash the bottom of the sphere, though the Oculus seems unaffected by this.
Description
The Oculus is smooth and spherical, about fifteen meters in diameter. It appears to be made of some black metallic substance, though the impossibility of taking samples or conducting potentially destructive tests means that its actual composition remains unknown... based solely on its appearance, various chemists have proposed as possible constituents laurite, magnetite, tetrahedrite, nichromite, black gold, and silver nitride. All of these identifications are tentative at best, and it could be that the Oculus is composed of a different substance altogether, or even (as many chemists believe) a material otherwise unknown—and of course it's entirely possible that it is not as uniform in composition as it appears, but that different parts are made of different materials.
The Oculus is not featureless; on the contrary, it is covered all over its surface by a complex network of recessed lines, round dimples, and occasional oblong projections. None of these irregularities is large; most of the lines are less than a millimeter in width, the dimples no more than thrice that, and the oblong projections not exceeding a centimeter. The most notable feature, however, is a pronounced circular pattern about six meters in diameter, made up of a combination of circular and radial ridges and depressions, larger and much more prominent than those elsewhere on its surface. It is this feature that gives rise to the Oculus's name, due to an imagined resemblance to a human eye, with the circle as the iris and pupil. (In a somewhat illogical usage, the circle is often referred to as the "Eye of the Oculus", or just the "Eye" for short.) The Oculus is also occasionally known as the "Death Star", after a superficial resemblance to a certain space station in a famous space opera setting.
Origins
The Oculus was first discovered in 2005, though given its out-of-the-way location it's quite possible that it had been around for much longer and simply hadn't been found before (at least not by anyone who survived to tell the tale). Since then, there has been no obvious change in its appearance or in its behavior; it seems to be exactly the same now as it was then.
Although the Oculus seems to be clearly of artificial origin, no one knows just who created it. The most common assumption is that it was constructed by one of the metarchs who rule Gallerra, as part of a plan to expand their territory or strengthen their grip on what they already possess. However, no metarchs have admitted to being behind it, and many have explicitly denied having anything to do with it. The metarchs most often implicated in the construction of the Oculus are Tangaroa (because of his connection with the ocean) and the Matriarch (because of her interest in technology and robotics), but there's no compelling evidence for either of them really behing behind it, and it's not at all obvious what benefit the Oculus would provide to any metarch in any case.
Other possibilities have been raised; some have suggested that perhaps the Oculus was created by some superhero as part of a plan to oppose the metarchs; others that it was fashioned by some inhabitant of—or even is itself some inhabitant of "another planet or dimension, perhaps here at the vanguard of a coming invasion.
Activity
The purpose of the Oculus remains obscure. It merely seems to hover in place, occasionally rotating. (The mechanism behind its hovering is as poorly understood as everything else about it.) The hovering is unpredictable, both in angle and in frequency; the Oculus may remain completely motionless for many days, only to spend the next day wildly rotating in every direction. It's popularly believed that the Oculus is observing things through its "eye", and that it rotates to focus on different objects, but there's absolutely no evidence for this, and it seems inconsonant with the fact that it seems as likely to rest with the "eye" pointing almost straight up into the sky or down into the ocean as it does with the "eye" in a seemingly more useful horizontal position.
Aside from its erratic rotation, the only time the Oculus shows any signs of movement or activity is when it is in danger of damage. This includes such trivial damage as attempts to scrape the surface to take a sample, as well as something as serious as a bomb. In any case, the object and/or person in a position to harm the Oculus simply disappears, after being briefly surrounded by a bright lime green glow. No remains or residue of the vanished people or objects have ever been discovered, and there is no way of knowing whether they are truly destroyed, or translocated perhaps to some other plane. The idea has been proposed that the vanished objects are in fact brought inside the Oculus, but given the sheer number and volume of such objects this seems impossible unless the Oculus is much bigger on the inside than it is on the outside.