Season 4, Episode 4:
MetamorphosisDean catches Sam in the act of using his powers, exorcising a demon with his mind. He's not overly thrilled about this, but before they can have a big fallout, Sam's phone rings. It's Travis, another hunter, who wants help catching track down a rugaru.Rugarus, we learn, look like normal people, until they get really hungry and eventually turn to cannibalism. It's genetic. Travis killed this rugaru's dad, but lost the kid.The Winchesters have different ideas on how to deal with it. Sam reckons they can't kill him until he gives them reason to- innocent til proven guilty and all that. Dean reckons they should deal with the problem before the body count piles up. Meanwhile, Travis figures out that Rugaru-man has got his wife pregnant, which means the cycle is gonna start all over again. He attempts to burn them both and get it over with. Doesn't work out too well for him. Rugaru eats him and goes full-on monster mode.Sam and Dean arrive, and he manages to lock Sam in a closet (though Dean knows closets better) and stares at unconscious Dean, trying not to eat him. Just as he is giving in, Sam bursts out and burns him alive. Kill it with Fire indeed. Dean is duly grateful, and later manages to say that though he doesn't have demon blood, he'll be there for Sam.
Body countFor this episode = 1 human, 1 demon and 1 rougarou.For the series so far = At least 258 humans (of which 3 were witches), 52 demons, 24 ghosts, 10 vampires, 6 changelings, 3 gods, 2 shapeshifters, 2 werewolves, 1 cat, 1 crocotta, 1 djinn, 1 rakshasa, 1 rawhead, 1 rougarou, 1 shtriga, 1 wendigo, 1 zombie.