In Korea, there are a few things we are not supposed to do at night. So when I was young, my mom asked me not to cut my nails at night. She said, "If you cut your nails, some animals like mice will eat your nails, and then they'll become you or they'll take your spirit." Basically, this belief is from the past when we didn't have electricity. If we cut out nails then night then, the room would be dirty because we couldn't see to clean it. So, we still don't do that even today.