Considering that people who play blind might lose a lot of their stat upgrades when they explore the wilderness, i think that as long as there is some sort of warning(some character shows up and warns you about these enemies) that exist in some way that every one will notice it and prepares a little bit. I think it would be a quite challenging and 'proper' enemy type.
Its a great enemy idea though, maybe they could be hard mode enemies or enemies that shows up later in the game's storyline.