From Eloquent Creature to The Monster Mash: Where did it come from?

"If the multitude of mankind knew of my existence, they would do as you do, and arm themselves for my destruction. Shall I not then hate them who abhor me?" the creature Pg. 69

So far this book is nothing like I thought it would be like. I knew going into it that the book would be different from the common idea of Frankenstein but I didn't expect this much difference. First of all Frank is the creator, not the monster which is weird to think about. Also the mental image I had of the creature was this green idiot monster with black plugs for ears. However, after reading the book now I picture the decomposing, sensitive, articulate monster. So where did all these misconceptions come from? How did his image get so morphed that he's become a goofy Halloween costume? There are definitely ties to the original but I feel like the main points the author was trying to make have kind of disappeared. This story has big themes of nature and discovery but the stories now are more about the horror. Much like the people who flee from the monster, today's society is more focused on appearances than on the deeper meaning.