10 Classic Doctor Who Enemies Who Need To Return

The Mara are one of the most interesting species in the whole Whoniverse, yet they've only ever made two TV appearances, broadcast a year apart. They're a sort of non-corporeal gestalt entity that inhabit the "dark places of the inside" and seek out hosts in order to inhabit the physical universe. They made their debut in the 1982 Fifth Doctor story, Kinda, in which they vied for control of the the Doctor's companion, Tegan. They made their second and final appearance the following year in Snakedance, which served as a direct sequel. It was a rare instance of continuity in Classic Who, with Tegan still dealing with her ordeal in Kinda.

The Mara do have a physical manifestation - that of a giant snake - but they are very much creatures of the mind. As such, they offer some truly bizarre and psychological visuals. In Kinda we are treated to some trippy dream sequences as Tegan fights for her mind, and it's captivating to watch. With this unique nature and imagery, it's no wonder that the Mara have remained popular among fans.

Now just imagine what could be achieved with modern special effects and storytelling conventions. Having a companion trapped in a nightmarish dreamscape, fighting for their mind, on the brink of sanity? It's fascinating stuff. While they're not the kind of enemy that could be a regular presence, like the Daleks, they definitely have the potential to make a huge comeback, perhaps even as a season-long antagonist. Make it happen, RTD.