Amemasu

The Amemasu is a colossally large rain trout, thought to hold up the world. When the Amemasu tires, devastation is left in its wake, subjecting the surrounding area to earthquakes and other natural disasters. There is a lake in Hokkaido that is said to be home to a particularly large Amemasu, with a head like a rock and a tail that stretched to the Kushiro River. An Ainu hero, Otashitonkuru, took a harpoon to poke out the eyes of the Amemasu. The fish fought back, and desperate to hold on to the harpoon, Otashitonkuru held onto a rock, and the Amemasu pulled so hard, that the rock became the island in the middle of the lake.