8. Prehistoric tape worm. This revolting creature appeared in the fourth episode of Primeval, which aired in March of 2007 in the UK.
Here, a flock of adorable dodos waddle through one of the series' colorful time anomalies into modern England, but a few of these extinct, flightless birds are carrying a parasite that can temporarily seize control of the host and act aggressively to assure reproduction. One of Connor's (Andrew-Lee Potts) friends, Tom (Jake Curran), is infected with the organism after a dodo bite on his arm. He soon suffers debilitating headaches, massive pain and increased paranoia as the worm inside him...grows. At one point in the episode, we see a high-resolution scan of Tom's skull, and this large, lively worm wriggling about inside it.
In this entry, Angel becomes trapped in a vegetative state while under the influence of a slimy worm-like creature called a Selminth Parasite. This creature causes hallucinations in its host, and in the episode, Angel dreams that Spike has replaced him as the champion of the Shansu Prophecy. Here, the worm is used as a weapon by a sinister agent (Eve), and alters the very mind-state of the host. Angel must wake up and remove the parasite from his chest, or live in a a nightmare for the remainder of his days...
After Walker’s ship, The Horatio explodes in an apparent accident, Picard fears there might be some truth behind his friend’s paranoia. He orders the Enterprise back to Earth, and there discovers that the Admiralty itself has been infiltrated by parasitic aliens bent on conquering the Federation from within. These small, crab-like aliens enter human beings through the mouth, and then completely control all higher mental functions. The small parasites also report to a much-larger, dinosaur-like “mother” being that has found a home inside Commander Remmick (Robert Schenkkan). The parasites die without this mother being in close proximity.
Here, Agent Scully (Gillian Anderson), sans partner, visits Utah to investigate a strange death. She soon runs afoul, instead, of a weird cult that believes a worm parasite represents the second coming of Jesus Christ on Earth.
Once inside the secret community, Spain learns that the strange group is led by hideous alien invaders: horrible crab-like creatures that attach themselves to the human spine and totally control minds. If the joining process goes wrong, humans are rendered deformed and nearly lobotomized.
Here, a nasty civil servant, Stephen Macy (Laurence Harvey) covets a co-worker's wife (Joanna Pettet) and attempts to off her husband with a parasite called an earwig. The murder scheme goes horribly wrong, however, when Stephen himself is exposed to the wee bug.