The first thing you need to know about the 1977 B movie
Thrust is the "last dinosaur" of the title—a big game hunter and (shudder) Lothario who is the last of his kind—but, rest assured, dinosaurs of the more traditional type play an important part in the story. During an expedition beneath the polar icecaps, the crew of one of Thrust's "polar borers" was almost entirely wiped out by what could only be described as a Tyrannosaurus rex. They had inadvertently found a lost world, isolated among the glaciers and heated by volcanic activity, and only one made it back alive. Thrust sees this as an opportunity to hunt the most infamous terrestrial predator of all time, and so he organizes a return trip to the domain of the Tyrannosaurus with Chuck, the surviving geologist; Bunta, a Maasai tracker; Dr. Kawamoto, a Nobel Prize-winning scientist; and Thrust's (for want a better term) love interest, Frankie Banks (played by Joan Van Ark). The portion of the movie just before the expedition takes off—in which Thrust and Banks flirt and make out—are probably the most horrifying parts of the film.
As would be expected, the motley crew make it through to the realm of the dinosaurs, but things quickly begin to go pear-shaped. A huge mammal—based in Uintatherium but called a ceratopsian (or horned dinosaur) by the team's geologist—almost stomps on Frankie as she snaps away with her camera, and when the team runs into the Tyrannosaurus on the following day they realize that no matter how fast they run, the lumbering, tail-dragging monster is only two steps behind. (And if you got both hair- metal references in that paragraph, well done.)
Things get even worse when the Tyrannosaurus makes it back to the team's camp before they do. After conducting an experiment to see if Dr. Kawamoto can be stomped into a pancake (the hypothesis was supported by the evidence), the Tyrannosaurus has a magpie moment and decides that it wants to add the big, shiny polar borer to its collection of bones back in its lair. As the Tyrannosaurus tries to find just the right spot for its new collectible, though, it wakes up a Triceratops that had been slumbering in the cave wall for some indiscernible reason. Face to face in the valley of bones, the men in rubber suits—oops, I mean dinosaurs—duke it out. (Guess who wins?)
With their only mode of transport lost, a terrible Tyrannosaurus on the loose, and a tribe of prehistoric humans making life ever more difficult, the surviving crew members try to eke out a living in the harsh land (though they apparently spend plenty of time grooming as they never look too dirty). They make it for a few months, but after one Tyrannosaurus attack too many (I would think one would be enough), Thrust and company decide to make a catapult to take down the dinosaur. With a little help from Hazel—one of the archaic people who took a shine to the group—the team creatures a wooden trebuchet big enough to put a dent in any large dinosaur.
Just after completing their European history practical, though, the team's geologist relocates the polar borer—they can finally go home!—but Thrust insists on staying. The intro song called him the "last dinosaur," after all, so he can't go while there are still other dinosaurs running about the place. That just wouldn't be right. After a bit of arguing and dithering about whether Thrust should return to the world they left, the final battle begins, and it doesn't hold back on the unintentional humor. My favorite moment? When the catapult is fired and the immense rock loaded into it strikes the Tyrannosaurus square on the head. Surprisingly, the dinosaur's skull collapses to absorb the shock of the impact before springing back into place - Thrust had not counted on his quarry having such a resilient noggin. In the end, the trap doesn't work, and Thrust is left on the beach of the prehistoric world, with only Hazel and his theme song to keep him company.
But I jest because there's a special place in my heart for The Last Dinosaur. It used to air on television relatively frequently when I was a child, and back then anything with a dinosaur in it was a must-see program for me. Even now, when I would like to think my taste in films has been refined a bit, I throw it in the DVD player every now and then. The acting is so bad, the dinosaurs are so crummy, and the soundtrack so cheesy that it's hard not to laugh at it. Without a doubt, The Last Dinosaur is one of the worst films ever made, but that's why I keep coming back to it.