"100-year-old egg", also known as "century egg", is an egg wrapped in something and buried shallowly for about 100 days, one day for one year. It is not difficult to understand that the year here is translated into age. Nowadays, with the development of technology, the number of days required to make preserved eggs is getting less and less. Preserved eggs look like rotten eggs buried for a century, so they are also called "century eggs".

The story about "Mommy Kaka" upstairs is very good, and I found a similar original. But it's a little long, so I won't post it. It is suggested that "Kaka Mommy" is the best answer.