Mrs. McMurtle, aka the Koekoeken, is the antagonist of the Creeped Out episode Cat Food.


The Koekoeken is a parasitic creature which needs a human host. At the beginning of the episode, it takes the form of Mrs. McMurtle, an elderly woman with white hair and glasses. At the end of the episode, it assumes the form of Kelly, Stu's sister.

The Koekoeken's true, monstrous form is never shown clearly, although Stu glimpses its silhouette while spying on Mrs. McMurtle.


In the episode Cat Food, Stu spies on Mrs. McMurtle while bunking off school. He sees her take delivery of several packages of cat food, which she seems to have no trouble carrying despite their size and weight. He watches her remove a false wall in her garage, fill a bath with the cat food and get in, after which her shadow appears to transform into a kind of monster. Stu searches for 'cat food bath creature' online and finds out about the Koekoeken, a legendary parasitic creature which needs the taurine found in cat food to survive.

After Stu tells his mum what he has found out, she goes to Mrs. McMurtle's house herself. Stu's mum speaks to Mrs. McMurtle and looks at the garage, but finds nothing strange. While there, she gets a phone call asking her to go in to work, and arranges for Mrs. McMurtle to babysit Stu.

When Mrs. McMurtle arrives, Stu tells her he knows what she is, and she tells him she planned to get his attention all along, and deliberately made sure he saw her carrying the cat food. She has been spying on him too and knows he breaks into his dad's study every term to copy exam papers. She also orchestrated the phone call to his mum in order to get her away from the house.

Mrs. McMurtle shows Stu a series of old photographs, all bodies she (the Koekoeken) has inhabited. She needs a new body and has her sights set on Stu's. However, the Koekoeken cannot simply take his body – she has to win it. Stu suggests a game of heads or tails, but Mrs. McMurtle knows he has a two-headed coin and tells him to choose another. She suggests a game of cards. Using his camera positioned beneath the table, Stu cheats and wins, and Mrs. McMurtle is forced to leave.

The next day, Stu sits down for breakfast with his sister Kelly. She speaks to him in Mrs. McMurtle's voice, revealing the Koekoeken has taken over Kelly's body instead. She reveals that she won a game of cards with Kelly by way of the same trick Stu used to beat her.

Powers and abilities

In the episode, the Koekoeken demonstrates the following powers:

  • Ability to possess a human body
  • Ability to transform from a human into its true form
  • Long lifespan (provided the Koekoeken is able to keep finding human hosts)
  • Superhuman strength

The Koekoeken has two significant weaknesses: it is unable to take a human host without first winning it; and it requires large amounts of taurine for sustenance.

Stu visits a website for information about the Koekoeken. It reads as follows: 'THE ORIGINS OF THE LEGEND: The Koekoeken (parasite) is a creature that has appeared in oral tales and legends all over the world. Deriving from ancient myths and folklore, it is a clever beast that is capable of living a thousand years, by tricking unwitting victims to play for their lives. References to these creatures have been found throughout history in art and literature.'


  • Stu: When she enters Stu's house, Mrs. McMurtle continues to keep up the 'old lady' act, offering Stu advice for dealing with his cold, even as she explains her plan. She is enraged when she realises Stu has won their card game by cheating.
  • Kelly: Having been unable to claim her first choice of human body, the Koekoeken instead targets Stu's sister. This suggests that, although she may have initially chosen Stu because of his cheating and lying, she has no qualms about taking the body of a more innocent victim.


  • Koekoeken is the Dutch word for cuckoo, another parasitic species.