Aired: Thursday September 11, 1997
Writer: Alexx Van Dyne
Director: Tim Eldred
Synopsis: A group of paranormal clowns that feed on laughter stalk New York City. The Ghostbusters chase one of them down and Eduardo traps a clown in a heartbeat, there's only one catch. Eduardo must replace the clown which he trapped by turning into one!
- Title Reference: According to the Merriam-Webster Dictionary, a killjoy is a person who spoils other people's fun or enjoyment.
- Guest star Susan Blu is also the dialogue director of the series.
- There are two versions of this episode. When this episode was shown for the first time, there was a brief one-frame animation goof -- the "clapboard" was visible for one quick frame during the scene where the Extreme Ghostbusters are in Ecto-1 discussing the vampire analogy. However, in subsequent airings, the clapboard was removed and the error fixed. I very seriously doubt we'll ever see the clapboard version again.