In The End of the World, we meet the “last human” Cassandra, who is purely face (or face-skin). According to him/her (Cassandra says she had husbands, but also says he was a “little boy” — as Cassandra seems more female than male, I will refer to Cassandra from here on as “she”) she isn’t a “proto-human” or “digi-human” etc.

This may sound stupid, but she doesn’t seem to have a brain, so my question is:

Where is Cassandra’s brain? And how is she alive?

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    How can a Being/Human without any sexual characteristics be described as male or female, anyway. Cassandra is effectively gender-less (unless that individual's sexual organs are kept in some box, next to the brain).
    – bitmask
    Commented Dec 3, 2013 at 12:19
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    @bitmask well Kassandra must have been born either male or female, as u can see i was referring to where she refers to her younger self. (she may have undergone a M2F gender change) Commented Dec 3, 2013 at 12:22
  • For the record, Cassandra was born a boy, but choose to become a woman later, hence the apparent discrepancies. All is documented in her wiki page, along with many spoilers (read at your own risks).
    – Eureka
    Commented Dec 3, 2013 at 12:51
  • @Eureka i guessed that (see above comment) Commented Dec 3, 2013 at 18:50
  • @tryingToGetProgrammingStraight it was just to confirm that her wiki page provides informations such as her original "male" name and such, among other spoilers ;)
    – Eureka
    Commented Dec 3, 2013 at 19:16

1 Answer 1


The brain of Cassandra O'Brien.Δ17 is located in a jar, under her frame:

Cassandra's BrainInAJar, from "The End of the World" episode

It is more clearly seen in the New Earth Doctor Who episode, the first episode of the following season, with David Tennant. This is another case of the BrainInAJar trope (Warning TVTropes link) often used in fiction.

Edit: As to how she can be alive, we can see blood or some kind of nutritive fluid pulsing in blood vessels: The base probably includes some kind of pump. Since she is almost only skin, we can also imagine that the liquid used to moisterize her also contains miscellaneous chemicals working by diffusion.

  • i just watched it (im going in order from 2005 - season 1) Commented Dec 4, 2013 at 10:37
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    @tryingToGetProgrammingStraight Just watched it some days ago too, even if I had the DVDs for months: That's why I answered so fast ^^
    – Eureka
    Commented Dec 4, 2013 at 11:13
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    You can see it even better in this link: markcordory.com/Site/Galleries/Pages/Dr_Who_2.html#3 You'll have to scroll through some other pics. It was made by a friend of mine :)
    – Pat Dobson
    Commented Dec 10, 2013 at 20:00

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