So I was playing Splatoon 2's story mode and in stage 13, dancing floors ink switcheroo, I saw some pixel art of the guy in the project, which I remade using the bitmap sprite mode. He might be an octorok, but I'm not sure...
The specific location is after the first octosniper and to the left of the flipswitch platforms, there are four tiles with this thing on them. *edit* yes, it's an octorock. I saw it in SwankyBox's region break of Zelda two.