A story my great-grandmother told my mom her sisters when she was growing up about why cats are bad.
Chuseok is the Korean equivalent to Thanksgiving. On this day, families prepare lots of food and offer them up to the ancestors. No one is allowed to eat it until the ancestors have had their share so you can't eat until the next day.
One day, the family cat ate the fish that was being offered to the ancestors. The mother grabbed the cat and beat it before throwing it out the house.
The cat, angry, never returned.
Later that year, the daughter learned she was with child.
Now, a traditional house is build above the ground. This is because back in the day, they would heat up coals/wood under the house to keep it warm. This is important because that night, the cat returned to the home and dug at the ground beneath the house. The cat returned every day and would dig at the ground more and more.
One day, some monks came to the house to ask for donations. The mother, being a devout Buddhist, obliged and invited them into her home to rest and eat. When they entered the home, one monk was overcome with a terrible feeling. He told the mother, "There is something evil in this house. Have you recently angered anyone?"
The mother thought long and hard and mentioned that she had cast out the family cat for eating an offering to the ancestors.
"Ah," The monk said, "You must be careful because the cat wants to harm your family. We can cleanse your house of the evil but first, we must get rid of the cat."
That night, the monks hid outside and watched as the cat went under the house. They couldn't see why it went under but they only needed to know the cat was visiting the house.
The next night, they laid out a trap. They placed a fish outside and when the cat came to eat it, they threw it into a bag and killed it.
One monk crawled under the house to see what the cat had done before. Under the house, the monk fond a small hole in the ground, like a grave for a small child, under the daughter's room.