5. Chameleons
Wow, aliens called chameleons; I wonder what they could do? Thats right, The Faceless Ones, a story set at Gatwick Airport, saw the Second Doctor face these pesky imposters pretending to be human who wanted to, yes, youve already guessed that too, take over the world. While their modus operandi and aim are hardly original in sci-fi, the chameleons are still chilling villains whose best feature is their scabby, featureless faces. Especially creepy in black and white. Brr.
4. Wirrn
Another fan-favourite monster who is mostly forgotten, the Wirrn were man-sized insectoid aliens who laid eggs inside human space travellers in Fourth Doctor story The Ark in Space. Although it helps that they appear in one of Tom Bakers finest stories its Alien before its time the Wirrn are themselves effective villains; their best (quite horrific) scenes come courtesy of the poor Human/Wirrn hybrids they create. The Wirrn deserve a proper comeback but have never got one fingers crossed for next year.