Chthonium is a roving malevolent force which will absorb into itself all light, energy, and matter it encounters until time-space is once again collapsed to a singularity. it was recently unleashed once more upon this plane by an american scientist researching the mystical properties of sound when his experiments inadvertently resulted in the release of this ancient entity from it's interdimensional prison, where it had lain dormant for untold eons since being vanquished long ago at the cost of several advanced civilizations.