Tumour alien
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"Tumour alien" is a title based upon conjecture.
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A tumour alien was a grey, blob-like parasite that attached itself to its victim's brain, causing symptoms that could be mistaken for Alzheimer's disease, eventually killing them. If it was disturbed, then it released a toxic gas. One passed through the Cardiff Rift and attached itself to Katie Russell. When she was operated on, it killed all of the surgeons, along with Katie. (TV: Fragments)
