I'm working on Bad Apple, so I didn't go for groceries and I won't do much of a post. But we've been talking about vampires on and off for a while and I saw an article that goes into the topic from a scientific perspective 411 on Vampires. I think my milkshake question is answered by this
"though laypeople might assume that a body would decompose immediately, if the coffin is well sealed and buried in winter, putrefaction might be delayed by weeks or months; intestinal decomposition creates bloating which can force blood up into the mouth, making it look like a dead body has recently sucked blood. These processes are well understood by modern doctors and morticians, but in Medieval Europe were taken as unmistakable signs that vampires were real and existed among them."