9. Third Doctor - Invasion of the Dinosaurs (1974)
The era of Jon Pertwee as the Third Doctor was a game-changer, to say the least. Hit with budget restrictions, the executives of the show needed a plot device for the show to keep expenses down, and thus, they decided the Third Doctor would be grounded on Earth by his own race, the Time Lords. The following five seasons were blessed by a fantastic lead actor, good scripts, and an astounding variety of stories, seeing as they could hardly change their locations. But sadly, the six-episode Invasion of the Dinosaurs was not meant to be one of those. Invasion of Dinosaurs had a good premise: Dinosaurs have begun popping up all over London, and no one knows why. They eventually learn someone is intentionally messing with "the Time Eddy", and they set out to stop him and the dinosaurs. Well, okay, maybe the premise isn't so good after all. But the main cause of complaint directed towards this episode has got to be the special effects (seen above). That's not a bad picture of good episode. That's a good picture of a terrible, terrible episode. What's saddest of all is that the bad FX and confusing plot twists wound up overshadowing the good parts of the serial. It had an excellent cast (in particular Elisabeth Sladen in the first season of her timeless character Sarah Jane Smith), and the director did the best job he possibly could have, seeing what he was working with.
If You'd Like a Good Jon Pertwee Story: You can't possibly go wrong with 1970's Inferno. This 7-part serial is frequently cited as being the single best story in the entire Classic Series. It handles the timeless "evil parallel universe" part perfectly, and makes GOOD use of constant plot twists. Also try Carnival of Monsters or The Sea Devils.