Cars is a charming, funny, well-crafted Pixar animated classic released in 2006. It was Pixar's last independently produced project before being bought by Disney entirely and has generated a staggering number of dark, macabre fan theories that run the gamut from genocidal annihilation to David Cronenberg-esque body horror.
The film - set in a world resembling modern-day Earth but populated by anthropomorphic vehicles - tells the story of a hotshot rookie race car who stumbles upon the small, rural town of Radiator Springs after getting lost on the way to the biggest race of his life. Through forming new friendships with different types of other cars, each with their own lives and rich personalities, he learns the importance of friendship and humility. So it only makes sense that fans looked at that premise and thought, "Okay, but how can I make this give people nightmares?"
Cars was followed by two sequels - the creatively named Cars 2 and Cars 3 - as well as several "non-canonical" spin-offs, including the 2013 film Planes, it's direct-to-DVD sequel Planes: Fire & Rescue, and multiple Disney Channel cartoon TV shows. Each one of these expansions to the universe - which is noticeably devoid of humans despite many, many indications of their past existence - have only added fuel to some truly disturbing entries in the genre of Disney-Pixar fan theories.