Matt Alt shot this fun video and wrote this blog post about how you can buy Rhinoceros Beetle larvae for only 98 yen each in Japanese shops. The roughly thumb-sized larva grow into big beetles that are popular pets in Japan.
Matt explains that they are known as kabuto-mushi, or "helmet bugs," for their exokeleton's resemblence of samurai armor.
And by the way, you can buy Matt's books on Japan here.