If that "squid inseminating a woman's face" incident didn't single-handedly fulfill your annual quota of heebies and jeebies, here's another medical oddity to sear your psyche.
In 2002, two doctors from the Lady Hardinge Medical College in New Delhi, India wrote to the journal Anesthesia & Analgesia describing the case of a 20-year-old patient who was recovering from a cesarean section. After the surgery, doctors discovered two unexpected bundles of joy:
While the dressing was being applied, the patient started complaining of nausea and vomited out a small volume of fluid. Following this, she felt a burning sensation in the throat [...] The burning sensation continued and in addition, she now felt some fullness in the throat. She became restless and while being transferred on the trolley, she put her hand in the mouth and took out a curled up tape-like structure from her mouth. On closer examination, it was noted to be a 128-cm long tapeworm. She appeared comfortable after this but about 5 min after transfer to the recovery area, she vomited once again and pulled out another tapeworm (64 cm) from her throat. Her vitals through the two episodes remained stable. The burning sensation disappeared after she pulled out the second tapeworm. On questioning, she gave a history of eating pork once in a while over the last few years.
To curb the potential transmission of tapeworm eggs, the study's authors helpfully advise, "We suggest that an anesthetist wear gloves while dealing with a patient who is vomiting." (Good advice in any circumstance.) And if your recommended daily dosage of animals jumping out of people's orifices hasn't yet been met, here's the case of a 15-centimeter-long Ascaris lumbricoides nematode getting stuck in a chap's ventilation tube. The Straight Dope has also catalogued some further instances of parasites making a break for it.
Hat tip to Alex. Top image via the Futurama episode "Parasites Lost."