An element with mind-altering properties, rendering the subject contemptuous of everything he lays eyes on. Many comments on blog posts are made under the influence of bilium.
Darwinium was accidentally created in the search for stable superheavy elements, and has an atomic number of 288. Its half-life is only a few microseconds, but in that time it is able to catalyse the combination of ordinary heavy elements to form more darwinium and other members of the darwinide family whose properties vary in many ways, and which can induce each other's transmutation or disintegration. The resulting intense process of natural selection, with upwards of 100,000 generations per second, has resulted in the rapid creation of entirely new forms of matter, faster than human understanding can keep pace with. Fortunately, it has not yet evolved the ability to digest any of the lighter elements. The few samples in existence have been isolated in aluminium containers, within which the finite resources cause the evolution to eventually peter out. The samples now appear to be quiescent, but there is no known way of destroying them. Theoretical calculations suggest that the introduction of as little of 1 gram of heavy elements might allow it to evolve the ability to digest every element down to hydrogen. Some argue that it is our moral duty to release the darwinide so that it may progress to transmute the entire planet and beyond into new life-forms beyond our imagination.
An element that needs to be excluded, on principle, from the Periodic Table, say some. Its specific hazards are described in the tome-like treatise "The Perils of Paulinium" , by Dudley Doright.
Alternates between a rigid state and a malleable state. Over time the malleable periods become more protracted, and the rigid state becomes harder to achieve.
Originally dismissed as mere hearsay, this element was re-discovered in the Australian jungle and is now used in the advertising business. Not as you might think a halogen, but a different klass altogether.