Samurai Helmet Beetle or Japanese rhinoceros beetle or Japanese horned beetle, or Kabutomushi (カブトムシ?), Trypoxylus dichotomus, is a species of rhinoceros beetle found in Japan, Korea, Taiwan and China.
It is sold as a pet in department stores in many countries of Asia, where it is also frequently depicted in popular media as a common cartoon character for various uses, for example much as cartoon bears, lions, or alligators are seen in advertisements and product labels in the United States.
Many children of Japan buy, or catch, these bugs and breed them. At hardware stores, males cost about 350-1000 yen, (around three to ten US dollars) while the females cost much less. The reason is because they have no horns at all.
Kabutomushi are a very popular subject in gambling, like Siamese fighting fish and cricket fights. In the most popular game, two different male beetles are placed on a log. The two beetles will battle each other, trying to push each other off the log, the one to stay on the log is the winner. This is a huge source and loss of money to many people, especially in the Ryukyu Islands.