This particular one is very interesting. "gato" does not originate from the word refering the animal, but from gatillar (triggering) that was slang for who used to pay for company (To put it in simple words). From there it evolved to several meanings, the most important one being the person that acts as gatekeeper for somebody more important (In jails and mobs).

that is what is was very, very often used to refer to the ex president Macri.