Among the many Dark Matter candidates, I wondered if there are any along the lines of the title.
The inner horizon of a black hole, with its mass inflation, and/or the high spacetime curvature, seems a violent enough place for the strangest things to happen that can anywhere, and tachyons (if these exist) seem to have enough counterintuitive properties that they might perceive far greater space volumes accessible inside black holes than outside, so that any created inside and straying out would readily tend to find their way back into the same or another black hole, with some energy change while in transit that would manifest itself outside the hole(s) as "dark mass" (assuming this was a fairly steady state process).
Piling speculation on speculation, one might further envisage that a tachyon which exited a black hole and lost enough energy outside (and hence gained speed) for long enough might greatly increase its chance of staying outside and thus manifest itself as dark energy.
The latter would also explain why the expansion of the universe is accelerating: If the average distance between black holes (between galaxies for example) is increasing with cosmic expansion, then on the preceding assumption slightly more tachyons can be expected to remain outside black holes, and so on.
It seems all this would make most sense (if at all) if tachyons appeared somehow "spread out" in normal space, like a field, as opposed to conventional sub-luminal particles.
Apologies if this is all too vague and speculative for some peoples' liking. I am not axe-grinding, quite the opposite, just curious to hear any informed comments on an idle fancy which is most likely untenable.