Oh god my heart

At first, I thought the spider girl was going to be some typical misunderstood cutie that was going to be persecuted for being a monster. Then you get the background on the spider girl and the shopowner starts to behave strangely, making her seem a lot less innocent. I figured that she was probably going to become dangerous as she got older, like her nature as a monster would. By the time they go to the abandoned village and into the house, I'm pretty sure the spider girl's pretty much started going full-on monster as I was ready to believe. Then she saves the shopowner and his assistant, showing them her mother. At that point I thought for sure that she really was good all along and simply wanted to see her mother. I would even go as far to say that things even got heartwarming at that point. Then she dropped the assistant to be fed to her mother in brutal double subversion, even going as far as replacing said assistant by taking her place at the shopowner's side. All I had to say at that point was mildly disturbed "...damn".

I still thought it was a good anime. I was just horribly caught off guard by the ending.