The demon cat in the Chinese movie Legend of the Demon Cat (妖猫传) only eats eyeballs. From 25 minutes into the movie:
I only eat eyeballs
In the movie, he eats both fish eyeballs and human eyeballs at various points. However, I haven't figured out why he has this peculiar dietary restriction.
Question: Why does the demon cat only eat eyeballs?
It's possible that it's because it's creepy, but I feel there should be more to it.