Season 4, Episode 14:
Sex And ViolenceSam and Dean enter a small town in Iowa, where three men have inexplicably beaten their wives to death. The guys realize that behind the murders is a Siren, a creature that can take different forms and desperately needs love, compelling people to kill others or themselves as a show of devotion. It looks however you want to it, but when the audience catches glimpses of its' reflection, you can see how dead and ghoulish it really looks.While investigating, the Winchesters bump into an actual FBI agent, who likes Dean's Impala, goes to the strip club with him, drinks with him and even knows his music. Sam is kept busy by a doctor, and ends up sleeping with her. Dean is convinced she's the Siren and refuses to meet up with Sam in case he's under her spell.That whole sub-plot was a redherring however, as the FBI agent is actual the Siren. It eventually puts Sam and Dean under its spell and pits the two brothers against each other in a fight to the death. The winner will get to be with it forever.During the fight, the brothers shout some harsh truths at each other. Dean says he's losing Sam, though whether it happened when he was in hell or before his eyes, he doesn't know, but Sam's keeping secrets and he doesn't like it. Sam retorts that Dean is an angst-ridden Woobie, and all he goes on about is the souls he tortured in hell, boo hoo.Dean is just about to kill Sam with a fireaxe when Bobby arrives and kills the siren.
Body countFor this episode = 2 humans and 1 siren.For the series so far = At least 286 humans (of which 5 were witches), at least 61 demons, 26 ghosts, 10 vampires, 6 changelings, 3 gods, 3 shapeshifters, 3 zombies, 2 werewolves, 1 cat, 1 crocotta, 1 djinn, 1 dog, 1 rakshasa, 1 rawhead, 1 rougarou, 1 shtriga, 1 siren, and 1 wendigo.