I've been thinking about what the opposite of the title "Dude, where's my car" would be, namely "Dude, where isn't my car?!" and how perhaps it could be like a post-apocalyptic story about a guy finding out his car was at ground zero and is now fallout.
So, for starters, with the letter A:
Original title: Aliens.
Negative title: Non-Aliens.
Description: Ripley actually turned out to be crazy for real, but the company was doing Vault-Tec style experiments with gasses to see how much havoc they could create aboard their ships. Everything else was a dream, except the hamsters of LV-426.