There, the unemotional alien composed of Light, the Zarn, is attempting to activate his drive system and escape from Altrusia. Marshall warns him that this kind of forced departure from the Land of the Lost is not possible, but Zarn stubbornly maintains his efforts to break out of the pocket universe.
To keep the Marshalls occupied while he does so, the alien sends “Fred” after the two men. Fred is a giant dinosaur robot….
As it turns out, Fred is actually a stop-motion dinosaur model made for the series, only sans skin. He’s just a metal dinosaur skeleton, in other words. Fred’s not particularly menacing, however, since he possesses no arms, and squeaks like Dopey or Junior. He’s actually kind of cute. We never get to his like again in the series.
They make the right choice to save the land of the lost, but Zarn’s beautiful ship of lights is crushed like a tin can. It’s rewarding that the writers allow the Marshall’s to feel this emotion of regret, and make the point (for the kids in the audience) that destruction has a price.. Violence may sometimes be necessary, but that doesn’t mean you have to enjoy it.