Mind-Boggling Optical Illusion

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You have to shake your head back and forth to see the animal hidden in this illusion.

Any guesses what the animal is? 

optical illusion

See the below!

The cat appears if you look at a very small version of the original illusion.

optical illusion

optical illusion

If you zoom out on the original illusion or look at a very small version of the image, the cat should become clear.