1. Bear Grylls copied Costner
In one of the opening scenes, Kevin Costner pees into a cup, pours it into a purifier, and drinks it right back down—beating Grylls out by 20 years. Sorry, Bear, people have been chugging piss since the 90s.
2. Waterworld is just Days of Thunder with boats
But, to be fair, Days of Thunder was just Top Gun with cars.
3. Kevin Costner plays a mermaid
Costner plays a drifter only known as "The Mariner" who's grown gills and webbed toes from some type of genetic mutation. He’s half-man, half-fish, so he’s technically a mermaid. Or, more accurately, a merman. MERMAN!