Well, a penny dreadful is a type of book that was very popular a very long time ago. They were called penny dreadfuls because they only cost one penny. They were kind of like scary stories or adventure stories, and they were usually really exciting to read.
People used to buy them all the time because they were very cheap and easy to read. They had really cool illustrations in them too! The stories were usually about things like pirates, ghosts, or monsters. Sometimes they were based on true stories, but most of the time they were made up.
Overall, penny dreadfuls were a fun way for people to read exciting stories without spending too much money. Today, we can find them in museums or in libraries, and they can be fun to read and learn about the past!