Sam and Dean finally manage to track down Azazel, the yellow-eyed demon that killed first their mother, then San's girlfriend. Unfortunately, Azazel's possessed their father. Fortunately, they happen to have the demon-killing Colt with them.
Which leads to a problem- they don't want to shoot and kill their father, even if it would kill the demon possessing him... Sam finally gives in and shoots his father in the leg, driving off Azazel. Thinking they've won, they head out in the Impala....
...Only to have a massive semi truck, driven by Azazel inhabiting a trucker's body, sideswipe them. Fade out on Sam, Dean and their father lying in the Impala, seemingly dead. I love that show, but this episode was brilliant.
Ohhh this is so easy, this be the BEST CLIFFHANGER, btw I thank you all for supporting my acting career Locutus will continue to serve on in the background of startrek, assimilating more races and perfecting those in the collective. YAY
The Season 2 ending of Blake's 7. Travis is dead, Blake is wounded, Star One is borked, and the Liberator stands alone against an entire fleet of Andromadan ships poised to invade the galaxy. Avon gives the order to fire and the credits roll. Classic.