So apparently Dean killed somebody’s sister. And, much like the Winchesters, shapeshifters like to get mad and get even. Their strength in numbers and handy conduit into Sam’s sense of reality, not to mention that little I-can-look-like-anyone,-even-your-brother! thing leads to considerable nastiness, and eventually drives out the Winchester’s Own strength in numbers – 2. Abject fluids abound, some good, some bad; some usually good but bad here. Sam gets used to the taste of his own blood. Dean gets used to the taste of Sam’s blood. It’s all the same in the end, and that’s how they know who’s who.
Next!
So apparently Dean killed somebody’s sister. And, much like the Winchesters, shapeshifters like to get mad and get even. Their strength in numbers and handy conduit into Sam’s sense of reality, not to mention that little I-can-look-like-anyone,-even-your-brother! thing leads to considerable nastiness, and eventually drives out the Winchester’s Own strength in numbers – 2. Abject fluids abound, some good, some bad; some usually good but bad here. Sam gets used to the taste of his own blood. Dean gets used to the taste of Sam’s blood. It’s all the same in the end, and that’s how they know who’s who.