Drained ocean
I have heard an old folk tale in several forms (the most recent the tale of the Five Chinese Brothers) about someone with the power to "drink the ocean" draining the water so that friends can gather fish from the sea bottom.
Unfortunately, when he is no longer able to hold the ocean in, his frantic waves for his friends to come ashore are ignored, and they are drowned when the ocean escapes.
Wonder if the origin of this story is an old tsunami experience.