In the Res. Notes. Astron. Astrophys. issue for Dec.:
Kokhirova, G. l. Zhang, M. Li, X-G. et al. Near-Earth Asteroids as the Parents of the δ-Cancrid Meteoroid Stream a. 125002 ad8c87
Dark comets are asteroids- nominally- that actually show (metaphorically) signs of activity, not a visible coma and tail. Usually, it’s nongravitational force that gives away comet-like emission. But there are other signs. The delta Cancrid meteor shower has no visible comet as its parent body. Instead, Kokhirova et al. found several asteroids, moving in a stream, to explain the delta Cancrids. Apparently, a parent “comet” (or asteroid) split into these smaller asteroids (or comets- TBC), with the δ-Cnc meteoroids as lesser debris. The meteoroids, with a higher surface-to-weight ratio, can be perturbed into Earth collision, where the larger, heavier asteroids have not (yet). The smaller “asteroids” may or may not have been completely depleted of volatiles by the breakup- that can’t be seen in telescopes. In other words, they might possibly reactivate, under good conditions.
Yet again, the cosmos doesn’t fit neatly into our pigeonholes. Pigeons are terrestrial, these are celestial. But apparently both shed.