I can actually see the human now with the larger upload. There is some real intense shading under the eyes and nose bridge. But I will never be able to unsee the kitty.
How in the heck are people seeing a cat? And what does that have to do with concentration? It's a dude's face from nose up, showing his noggin'. The thing that exerts mental power.
Bottom of the guy's nose is the cat's chin, if that helps.
It's far harder to see in the enlarged version, so whether you can see it at all may depend on the size of your screen.
I've always seen this.. and many many other icons for skills/passives and wondered if the art designers were seeing how far they could get without being caught.
The game is up artists, we've found your foolish drawings.
P.S. there's many more weird looking ones, especially in the DK tree.