An anomaly found on
the X-Files, a popular sci-fi show that ran for 9 seasons, and spawned many other take-offs involving slightly-similar circumstances. (
CSI and other shows like that can be argued to have been influenced by the X-Files)
At any rate, the super soldier was, as its name suggests, a genetically modified person, often nearly indestructible. One way of destroying it would be to somehow lure it near a large formation of rocks that contain copious quanitities of iron, which would then attract its metal body and kill it.
Also can be used to describe players of sports that are seemingly awesome at everything, or just incredibly good at one thing.
An amazing person, colloquially