The most interesting fictional adversaries have more in common than they do in conflict: Holmes and Moriarty. Gandalf and Saruman. Kenobi and Vader. Burger King and Ronald McDonald. What may make their 'familiar contempt' even more intriguing, perhaps, are the instances where they must put aside their differences and work towards a common goal -- typically their own survival. We present, as a popcorn-and-simple-pleasures example, the Doctor and the Master trying to jointly outwit an alien force that is quickly outgrowing and outmaneuvering them both, no thanks to the inherent greed/stupidity of a few humans in power.

This gem from 1971 has Pertwee and Delgado at their finest, wardrobe and special effects at their most questionable, and a story that just pops.

(Also: electro-pasta-beasts, 'embiggened' frogs, and mumbling country bumpkins clumsily riding bikes into freezing ponds. This is Classic Who at some of its finest -- production agony and ecstasy in a single story.)

BONUS: Enjoy play a round of "U.N.I.T. Must Have a 'Star Labs' Division", an alt-universe character improvisation game. Coming soon to a convention near you!