When the surface isn't enough to contain the adventures of Doraemon and friends, it's time to go underground.
Doraemon: Nobita and the Knights on Dinosaurs is a 1987 anime film and the eighth movie from the Doraemon franchise, based on the installment of Doraemon's Long Tales of the same name.
After Nobita and friends implored Doraemon to create an underground hideout for themselves, they discovered a hidden world beneath the earth's surface where dinosaurs still exists, having escaped cataclysm millions of years ago. An earlier misunderstanding leads to Suneo being stranded underground, sending Doraemon and friends to embark on a rescue mission where they meets Banhou, a dinosaur knight belonging to a hidden civilization of humanoid dinosaurs, whose ancestors - the troodont Stenonychosaurus - have evolved into a human-like state, living in a massive subterranean city called Enriru.
But after a rendezvous with Suneo, a sinister plot is uncovered from the raptor-men. Something which tells Doraemon and gang the noble knight of dinosaurs isn't who he seems. And the surface world is facing an imminent invasion...
Doraemon: Nobita and the Knights on Dinosaurs contain examples of:
- Alternate-History Dinosaur Survival: Unknown to humanity, dinosaurs still live in an underground civilization and evolved into a human-like state. At the end of the movie it's revealed that the responsible for this outcome was caused by Doraemon when he, in a last resort to save everybody and escape the destruction of the meteor, activates the Pop Basement gadget and evacuated all dinosaurs into it.
- Been There, Shaped History: The underground civilization of Enriru, created on the day of cataclysm which wiped out the dinosaurs 65 million years ago, was actually made by none other than Doraemon himself when he, in a last resort to save everybody and escape destruction, activates the Pop Basement gadget. In a hurry, Doraemon forgot to adjust the size and unintentionally creates an underground land the size of a small island, at which point the gang then use the Momotarō Pills to lure as many stray dinosaurs underground as they could, saving certain pockets of the dinosaur population from extinction. From there on the underground dinosaurs begin growing and evolving...
- Beneath the Earth: The plot of the story is kicked off when Nobita and friends convinced Doraemon to create their "own" underground hiding-place using the Holewhere. And then they discover Enriru, an underground civilization where dinosaurs still exist, with the troodonts evolving into a human-like state.
- Big Damn Heroes: Banhou, the titular dinosaur knight, making his introduction in the story by saving Doraemon and gang from the Naga tribe. He did it again later when the gang gets captured by the Naga while attempting to escape Enriru.
- Blinded by the Light: The Show-off Bomb, a futuristic Light Grenade variant which emits powerful flashes of light and makes a lot of sharp noises, but doesn't leave any injury. As Doraemon and friends have no intentions of actually hurting Banhou and his soldiers, the final battle have them throwing dozens and dozens of Show-off Bombs at the dinosauroid army.
- Cassandra Truth: Suneo's attempts to convince everyone he had seen dinosaurs is met with absolute ridicule and laughter, not helped by the fact that he was the one who made fun of Nobita for believing dinosaurs still exist first.
- Caught on Tape: After Suneo's claims to have seen live dinosaurs are laughed off by all his friends, he decide to bring along a camcorder to prove he's telling the truth. Said camcorder proves handy when Suneo gets lost underground, but Nobita managed to find the device, out of battery. Playing through the footage reveals the hidden entrance of the subterranean dinosaur world.
- Comet of Doom: The dinosaur people, blinded by their mission to wipe out mammals' ancestors, eventually found out what caused their extinction was not mammals, but is in fact a comet.
- Cool Helmet: Banhou and the dinosaur knights all wear impressive-looking helmets resembling dragonflies, which conceals their identities completely. So much, to the point that Doraemon and gang are aghast seeing Banhou without his helmet for the first time.
- The Cretaceous Is Always Doomed: The final battle taking place 65 million years ago where Doraemon and friends takes on Banhou and the rest of the dinosaur-men army is interrupted by the very meteor that triggered the extinction event that wiped out the dinosaurs. Which quickly puts the battle on hold as everyone present in the scene quickly retreats.
- Dinosaurs Are Dragons: The title would become Doraemon: Nobita and the Dragon Knights if the Japanese title was to be translated directly.
- Domesticated Dinosaurs: While the dinosaur-men population of Enriru have evolved to surpassing human levels of intelligence, they still have dinosaurs domesticated either as beasts of burden, for riding, or as pets.
- Dumb Dinos: Zig-Zagged. While the dinosauroids are an aversion, being troodonts that evolved to a level of sapience beyond humans, the other dinosaurs are still non-sapient wild animals, with the carnivores relentlessly chasing after the protagonists.
- Exact Eavesdropping: While the gang tries challenging each other to a race on domesticated ornithomimids, Nobita, lagging behind as usual, ends up being flung into a restricted building in the underground world, and conveniently overhears a discussion involving the underground army intending to invade the surface world.
- Fantastic Light Source: Despite being underground, Enriru and the surrounding subterranean civilizations are still well-lit, thanks to glowing funguses on the ceilings of their world. Nobita (while showing off how to use the Takecopter to Roo) accidentally bumps his head on the ceiling and voila, some glowing dust from the fungus gets rubbed off on his hair.
- Furry Confusion: Despite being living underground for 65 million years, majority of the dinosaurs are still savage, mindless beasts, with troodonts being the only dinos to have evolved into humanoid beings having their own race, culture, language, and capable of building machines and weapons.
- Giant Wall of Watery Doom: The final battle between the gang and the raptor-men gets cut short by the meteor responsible for wiping the dinosaurs hitting the Atlantic Ocean. And then, a massive tsunami heads for the coast... Banhou and his knights is forced to retreat back into their vessel, while Doraemon starts rummaging for a useful gadget and took out the Pop Basement.
- Hollywood Natives: The Naga tribespeople, despite being dinosauriods, are depicted in the stereotypical native gear, having painted faces, wear loins, and are shown as hunters who kill stray dinosaurs for sport. They're also the sworn enemy of the civilized dinosauroids of Enriru.
- Humans Are Ugly: Downplayed, but when Nobita and friends visibly gasps out when seeing Banhou without his helmet for the first time, and sheepishly comments that they're not quite used to how he looks. Banhou retorts that he thinks humans from the surface are far more unusual and odd-looking.
- Knightly Sword and Shield: Banhou and the rest of the dinosaur knights use these weapons as their default equipment.
- Living Dinosaurs: Earlier in the story, Nobita tried convincing his friends that there are dinosaurs still alive on the surface, which results in much ridicule thrown at him. And then, Suneo (who laughed loudest) ends up seeing actual dinosaurs.
- Lizard Folk: The underground dinosaur-men are descendants of troodonts who evolved into a humanoid form, based on the old speculative biology that troodonts would develop into a humanoid form had they survived and achieved sapience.
- Nice Guy: Banhou, the titular dinosaur knight, despite his reputation as a fearsome warrior unbeatable champion, is still a really decent guy. The same goes for his younger sister, Roo, who gladly helps her brother as caretaker for Doraemon and friends and sees to it that her brother's guests are treated like at home.
- No Antagonist: The first Doraemon movie that doesn't have a main villain. Heck, there's no "bad guy" character whatsoever in the entire story.
- Sauna of Death: This nearly happens to the gang when they're aboard Banhou's ship en route to Enriru, when they realize their quarter's temperature is suspiciously rising. Gian and Nobita start removing their shirts, and then couldn't stand it anymore and began dropping pants (much to Shizuka's embarrassment who began shielding her own eyes) when Banhou's voice suddenly comes from a nearby loudspeaker telling them there's an air-condition remote in the room. As it turns out their ship is currently passing Hawaii, through an underground volcano.
- "Shaggy Dog" Story: Nobita's motivation for requesting Doraemon for an underground hideout is to hide his tests marked zero from his mother. After everyone manages to evacuate as many dinosaurs as they can gather into the underground, Gian and Shizuka start worrying about the items they left behind underground, and Banhou assures them that they'll receive them in the near future. Unfortunately for Nobita, his mother receives the tests he had hidden away earlier... and the story ends with Nobita and Doraemon fleeing the house via bamboo-copter, all while Nobita requests for Doraemon for a tool to go underground again.
- Time Machine: The Top Secret project of the underground people turns out to be a time-traveling troop transport, used for sending their army 65 million years to the past in order to exterminate all mammals so that dinosaurs may rule the world. With Doreamon, Nobita and all their friends being the only ones who stood in their way of conquest.
- Unwilling Suspension: Doraemon and gang, hanging from atop an archway after being captured by the Naga tribespeople for the second time.
- Well-Intentioned Extremist: Banhou, the Pope of the Dinosauroids, the Dinosaur Riders and the army of dinosaur-men wanted to invade the surface world by time-travelling to 65 million years ago and wiping out the ancestors of mammals, because they believe mammals were the ones who wiped out the dinosaurs in the past, forcing the surviving dinosaurs to retreat underground. Little do they know about the truth about the meteor about to hit the Cretaceous...
- White Flag: After the initial retreat of the final battle, the raptor-men army resurfaces again only to see Doraemon waving a white flag, signalling a ceasefire for negotiation. It was here Doraemon uses a holographic projector to reveal the truth to Banhou, the raptor-men commander, and the raptor Pope - what actually killed the dinosaurs.
- You Can't Fight Fate: Despite Banhou's protests, the raptor-men Pope actually said this trope almost word-for-word, saying that if their ancestors, the dinosaurs, are fated for extinction, they will accept their fates. Luckily Doraemon suggests that they Take a Third Option by offering to evacuate as many surviving dinosaurs underground as possible, so they may evolve in the millions of years to come - thereby ensuring the existance of the underground dinosaur-humans in the first place.