UGH! I SO wished they'd stayed closer to the book last night. For all of you who haven't read the book, the surprise security guard was supposed to be Elvis... not Sam. According to the books, when Elvis was thought to be dead, he was still in a comatose state when he was in the morgue. The morgue worker was a vampire and he turned Elvis into one, too. Only Elvis goes by Bubba now and doesn't want people to speak his human name. He is a little slow because of all of the drugs/alcohol that were in his system when he was turned. That screwed things up a bit. Elvis/Bubba likes making meals of cats instead of humans. He's a very placid vampire who will become as violent as the others if someone crosses what he's supposed to protect.
Bubba shows up periodically within the books when different things are going on. I wonder if Graceland wouldn't give HBO the rights to use Elvis' likeness in this show and that's why they wrote him out of it. It is explained that vampire Bubba is the cause of all of the Elvis sightings after his death. I thought it was great comic relief in the books.