I honest to gracious am not understanding this trend. This is worse than the Tickle Me Elmo that was popular awhile back. People pay well over $100 for a plastic egg with some sort of upcycled Furby inside - and they fight in stores for the privilege to do so!
My children don't even know what this thing is and it's just as well. No way I would spend that kind of money on some cheap plastic toy that will be ignored in a month.
Are you unsure of what this Hatchimal thing is all about? I was... so I found this video. It confirmed all my biases. Yep, it's just a plastic egg with a toy inside. Someone is making a lot of money this Christmas season.