Recent studies of low-redshift type Ia supernovae indicate that half explode from sub-Chandrasekhar mass progenitor white dwarfs. This talk explains how asymmetric dark matter would ignite sub-Chandrasekhar white dwarfs, and form star-destroying black holes inside old neutron stars inhabiting regions densely populated with dark matter. The anomalously high r-process abundance of Reticulum II and explanations thereof, including dark-matter-induced neutron star implosions, will also be discussed.