It’s a double feature of extraterrestrial terror, as Sundance presents 1979’s Alien, followed at 10 p.m. ET by its first sequel, 1986’s Aliens. Both star Sigourney Weaver as the resourceful Ripley – but the two Ripleys are decidedly different, as you’ll soon learn, if you don’t already know. After one encounter with that shape-shifting terror, who wouldn’t be a little changed?