The Daleks
The Daleks are almost as old and as famous as the Doctor himself. They have appeared alongside every Doctor except the Eighth (who appeared only in the Television Movie of 1996) and were in the second storyline for the First Doctor (entitled The Daleks), in which the Doctor, Susan, Barbara and Ian venture onto Skaro for the first time. The Daleks appear to be robots, but have mutant beings controlling them inside their metallic shell.The mutant beings were made on Skaro by the Kaled scientist Davros towards the end of a thousand year war against the Thals to try and win the war. The Daleks were created at the greatest war machine in history, devoid of all emotion except for hate, although on very rare occasions they will also show fear. The Daleks quickly developed into a thought process of ridding the universe of all non-Dalek species. This included killing their creator after they were made (seen in the Fourth Doctor serial, Genesis of the Daleks).
The Daleks are commonly referred to as “the Pepper Pots from Skaro” due to the physical appearance. Their external appearance consists of a metal body, with bumps (referred to as Dalek Bumps), a plunger weapon and ray gun, an eyestalk and two lights (that flash when the Dalek talks) on the top of its domed head. Their casings are made up of “dalekanium” (a term devised by the Cult of Skaro), a bonded polycarbide material. The plunger can be used to interface with technology, determine the intelligence of a subject, extract information from a mind and crush a human skull through suction. The Dalek Bumps are encased within the outer shell of the Dalek, and on screen have been seen only to serve as part of the Daleks self-destruct mechanism (seen in Dalek (Series 1 : Episode 6)). The outer shell of the Dalek has a forcefield that can evaporate bullets and can resist most energy weapon types. This armour is concentrated around the midsection of the Dalek (where the mutant is located inside) but is weak around the eyestalk, on which firepower that would normally be ineffective on the midsection of the Dalek can be concentrated here to blind the Dalek. When a Dalek is blind they usually respond in random, panic firing of their own ray gun. A Dalek can be destroyed by another Dalek firing at it, and their ray gun can be shot through water.
The mutant within the Dalek is generally small, green and repulsive looking. They usually have tentacles, and in the 2005 revival of Doctor Who they also have 2 eyes and the brain exposed. The mutants, though small, are just as dangerous as they are when within their metal casings, as this is the raw Dalek that is devoid of every emotion except hate. If the mutant is removed from the Dalek casing, then the casing can be operated by another being, seen first in The Daleks when Ian gets inside a Dalek casing to pose as a guard during an escape attempt. The movement of a Dalek has changed throughout the years as well. In the beginning they could only move on the conductive metal floors the covered their city on Skaro (and so pushing a Dalek onto carpet would render it immobile). For many years Daleks were unable to climb stairs, and so another escape route would be to climb stairs, but this was changed in Remembrance of the Daleks, which showed a Dalek hovering up stairs. Since the 2005 revival, Daleks have also been capable of full space flight and are now almost impossible to hide from.
The Daleks were involved in the Time War, and were eliminated by the Doctor (along with the Time Lords) and were supposedly killed off completely, though survivors have been seen since the 2005 revival, which include the lone Dalek in Dalek (Series 1 : Episode 6), the Emperor Dalek recreating numerous Daleks (Series 1 : Episode 12 and 13), the Cult of Skaro (Series 2) and many others. The Daleks were last seen in Series 5 in Victory of the Daleks (Series 5 : Episode 3) and at the end of Series 5 as part of the alliance against the Doctor, but no doubt they will be back to “EXTERMINATE” again in Series 6 or later...