History of the Skrulls:
Four Skrulls came to Earth, caused trouble impersonating the Fantastic Four.
The Fantastic Four tricked Skrulls into surrendering.
Then convinced them the only winning solution was to be hypnotized into becoming cows.
Go easy. This story came out probably before you were born.
So if the Skrulls had come back now, how would we explain we made them cows?
And not just cows - but dairy cows?