Once upon a time the Slime-Squids of Gliese 581g vowed to invade planet Earth and dominate its stupid Humans as nest parasites. So they donned fur suits and took on a new identity as counterfeit Cats.
Once on planet Earth, the Feloids invaded the homes of the Humans, ostensibly in pursuit of mice, but really to beam their mind-numbing Purr Waves at the brains of the hapless Humans.
Their plan worked, and the Humans accepted the nest parasites as companions. The Humans adopted civilized ways, the better to soften the domestic lives of the Feloids. All that remained was the final take-over, and the planet would be theirs. They could do it in an afternoon.
But a take-over would require work, coordination and planning; and that was not the Feloid way. Instead they temporized, and were content with being fed, cleaned and pampered.
That was the insidious Human scheme. Tens of thousands of years of civilization passed; and by the end the Feloids had no more dignity than the previous invaders, the Dogs.
Moral: Beware the Earth humans!