Cora Lake is a location found in Breath of the Wild.
Breath of the Wild
The Cora Lake is located directly south of the Lake Tower. Water from the Cora Lake flows into the Menoat River and eventually out into the Faron Sea. Within the water itself, there are some Armored Porgy and Mighty Porgy swimming around, along with some Hearty Blueshell Snails that will occasionally wash up. There are some enemy Water Octoroks and Blue Lizalfos in the area as well.
Nearby Korok Seeds
Check the nearby clump of bushes for the hidden rock, and complete the pattern.
Pick up the rock.
First, find the cube under the water, then solve the Magnesis block puzzle. Will need use Cryonis to get close enough to the puzzle.