Doctor Who has been on the air for almost sixty years, amassing an impressive 862 episodes (and counting) on television since it began way back in 1963. Over the decades, the show has unleashed a host of enduring villains upon the public, tailor-made to haunt their nightmares. From Daleks and Cybermen to more recent creations like the Weeping Angels, the Doctor has a rogue's gallery like no other!
But what of those one-off enemies? The fiends that sprang up for a single story and then vanished, never to trouble the Time Lord again. Here is a list of some of Doctor Who's best one-time foes (not including appearances in any of the spin-off media surrounding the series).
10 The Mechonoids
The Mechonoids (sometimes spelt “Mechanoid”) were created at least in part with merchandising in mind, a race similar to the Daleks, but with their own quirky gimmick.
Their appearance in the 1965 serial "The Chase" rescues the rather dull adventure in the final two episodes, raising the stakes considerably by giving viewers an exciting firefight between the mechanical spheres and the iconic Daleks. While the Mechonoids didn't quite capture the imaginations of fans at home though, they did have an afterlife in various comics and audio adventures.
9 Tereleptils
The Tereleptils are a far cry from some of Doctor Who's more warmongering enemy types. They're an intelligent, sophisticated race with a penchant for creating beautiful-looking androids. This only makes them more dangerous.
In their solo television outing (1982's “The Visitation”), a small band of criminal Tereleptils planned to wipe out the human race without mercy, by way of a genetically-altered variation of the bubonic plague. They also managed to destroy the Doctor's Sonic Screwdriver, and his trusty tool wasn't seen on-screen again until 1996!
8 The Flood
“The Waters of Mars” (2009) was notable for introducing us to a much darker aspect of David Tennant's Doctor, but its monsters were just as frightening.
Using the age-old Doctor Who trick of making everyday things seem terrifying, as well as tying into the then-recent discovery of actual water on Mars, The Flood are a grotesque creation that tap into so many base fears. Contaminated water, humanity's literal life source, oozing through any crack and crevice, seeking to turn its victims into cracked, milky-eyed zombies? Pure nightmare fuel.
7 The Wirrn
Pre-dating Alien by four years, “The Ark In Space” (1975) introduces us to the deadly Wirrn, whose modus operandi is vaguely reminiscent of their Xenomorph cousins.
Inspired by the reproductive cycle of the Eumenes genus of wasp, the Wirrn are giant insects which inject their larvae into a host (in this case, human). Said larvae then take over whoever it is occupying, consuming them from the inside out. As an extra-grisly side-effect, they also absorb the knowledge and memories of their occupant.
6 The Reapers
The time vortex is host to an array of unusual beings, creatures that exist outside of the parameters of regular chronology. When reality starts to crumble and these monsters bleed through into our own universe, that's when things get really bad.
The Reapers are one such species, swooping onto screens during Doctor Who's 2005 comeback season, in the heart-breaking modern classic, “Father's Day.” Born out of the Doctor's meddling with companion Rose's personal timestream, these bat-like beasts tried to devour anything that shouldn't exist in that particular timeline.
5 Vashta Nerada
“Daleks. Aim for the eyestalk. Sontarans. Back of the neck. Vashta Nerada. Run. Just run.” And so says the Doctor, in 2008's “Silence in the Library,” the first episode of a two-parter featuring the dreaded Vashta Nerada.
These microscopic air piranhas can be found on most planets, dwelling in the darkness. When swarming in large numbers, they can strip the flesh off a person in milliseconds. There's no way to stop them, and once they latch onto their victim, casting a second shadow, it's already too late.
4 Raston Warrior Robot
The only new monster to appear in 1983's celebratory “The Five Doctors,” the Raston Warrior Robot is an athletic, multi-talented killing machine.
In a story featuring multiple Doctors, a host of companions from the past and present, as well as a menagerie of classic foes, it says something that the Raston Robot manages to remain in the memory. This is in no small part down to its ruthless massacre of a horde of Cybermen in one of the episode's most iconic scenes.
3 Vampires
Vampires have appeared in a variety of forms throughout Doctor Who's past, but each separate appearance has been a different species, whether they be the fish-like Saturnynes or the fiendish Plasmavores.
In 1980's “State of Decay” though, the Doctor comes face to face with the real thing. He meets a small group of vampires, led by the ancient King Vampire who once fought the Time Lords in a colossal war. They're a regal, bloodthirsty clan very much inspired by the gothic Hammer Horror movies of the 1950s and 60s.
2 The Rutans
Shapeshifters are nothing new in science fiction, and certainly not in Doctor Who either. But 1977's “Horror of Fang Rock” introduced us properly to the Rutans, a race mentioned several times before in the series.
Coming across like a green electric jellyfish, the thing the Rutans are most famous for is their on-going war with the Sontarans (who gave their blobby enemies a little nod in their most recent appearance). With a softer, more malleable form than their stockier rivals, there's a nice contrast between the two races which would make great viewing, should they ever appear together on-screen.
1 Krynoids
“The Seeds of Doom” (1976) is an all-out classic Doctor Who adventure, taking inspiration from both The Day of the Triffids and The Thing From Another World.
The Krynoids are intergalactic, sentient plants that take over human hosts and transform them into gigantic man-eating plants. They can control other plant life and can utilize the vocal cords of whoever they've consumed. They're one of the Doctor's most unstoppable foes, with a single Krynoid seed capable of wiping out humanity.