Oniguma is a Japanese Yokai monster folklore in Kisodani Valley, Nagano Prefecture, and mentioned in a book "Ehon Hyaku Monogatari" in 1841.
An old bear became yokai because of its age. It doesn't really come down to civilization, but it appears in dawn, takes domestic animals and eats in the mountain.
It has enormous power that just one push can kill a monkey. A person saw a huge bear pushing a giant rock into the valley. Later on, 10 people came to see the rock and tried to move, but it was too heavy even with 10 people.