The Devil possesses Marlena, Days Of Our Lives' plucky doctor, and causes her to manifest powers such as laser-beam eyes and projectile vomit, which coats her longtime love-interest John completely. Greatest soap-opera plot ever.
This video, which the incredible Dave Campbell linked to, is a compilation of all of the greatest scenes in the "devil possession" storyline ever. It's all fantastic stuff, featuring the classic soap-opera acting and fake backgrounds while people freak out about how to stop the Devil from wreaking havoc in Marlena's body. But by far the best bit comes around 7:55, when Marlena busts out the aforementioned laser eyes and face-spattering puke. It's the perfect thing to watch before tonight's Supernatural episode — I half expected the Winchester boys to bust in and sort it out.