CAT EULA

Cats are property. Property cannot be "authorized", cannot "act", and cannot make decisions. The cat is merely a tool she uses to push the button.

"I didn't sign that contract. My pen did. Sue it."

You're confusing two things...

You can only authorize another adult to act on your behalf as your agent.
You can utilize as an instrument anything, animate or inanimate, including a pen, a knife, a cat, or another person. I cannot claim my pen signed the contract, my knife stabbed you, my cat clicked the EULA, or Bob committed a battery on you when I shoved him into you against his will, and that I am thus responsible for none of the above: all of them are instruments of my will to cause that action. As I intended the action, the instrumentality is irrelevant.