Revenant: of uncertain origin and nature
The Revenant was found in the Portal environment, but it's biology (or lack thereof) defies scientific explanation so thoroughly that it has not been classified at this time.
The Revenant for all practical appearances is an animated, bipedal skeleton with varying amounts of attached gore. Examination of perished specimins reveals that the weapons attached to the shoulders of its jacket appear to be made with similar technology to that of the alien-modified monsters within the Portal environment. Clear understanding of the Revenant's function stops there.
Postmortem, the Revenant is a pile of bones, with no attaching connective tissue between the bones, no mechanical devices except for the weapon on each shoulder, and no working organs. Parts of ligaments, organs, and small amounts of extensively damaged muscle tissue cling to some of the bones, but do not appear to have recently performed any animation or biological function. Genetic analysis and identification of the remains were inconclusive due to consistant, massive cellular damage throughout all portions of all collected samples. The remains also emit a strong smell of decay, the onset of which is sudden and begins at the moment the Revenant ceased to be animated.
In the "animated" state, the Revenant's bones behave as though they are connected at the typical bipedal points at approximately the correct angles. The Revenant apparrently supports itself on its two legs, is able to stand and run, and it exhibits aggressive behavior similar to the (other) Portal organisms. Its attack involves either a powerful physical assault with its fists or, when the target is not within easy reach, its weapon fires projectiles at the target. The projectile is sphere-shaped, self-propelled, and moves at a relatively low speed for such a projectile (estimated 20mph). It flies in a spiral pattern at least initially, but homes in on the Revenant's target and approaches it. The projectile is only capable of making wide turns toward its target, and this is why the flight pattern can sometimes remain a semi-spiral. It is even possible (although not simple) for the target to move into the correct position relative to the projectile to cause the projectile to orbit the target without striking it.
The Revenant remains an enigma.