Kuroboko Rock is a volcanic bomb (projectile) carried from the top of Mt. Hakusan to the edge of the Mida-ga-hara plain by pyroclastic flow. Volcanic bombs are expelled during highly explosive volcanic eruptions caused by high gas pressure. The Kuroboko Rock is andesitic in chemistry, and after being expelled from the volcano as a liquid, cooled before falling back to the ground. Rocks like this are often found in the Mida-ga-hara plain.

The Kuroboko Rock is on the way to the summit of Mt. Hakusan when hiking from Bettou. It provides a great place to rest and lookout over the mountains.