Abstract: What is dark matter, the mysterious predominant constituent of all matter in the Universe? As I will show, primordial black holes from the early Universe make an attractive non-particle dark matter candidate, with intimate connections to astronomical puzzles like the origin of heavy elements (gold) as well as ongoing boom in gravity wave and multi-messenger astronomy. In fact, primordial black holes from the general formation scenario of bubble multiverse might have already been seen by Subaru Hyper Suprime-Cam.