Fun Vaccum

The fun sucker is a person who, by no fault of their own, can completely ruin a humourous conversation by generating a massive hole in the fun-continuum by saying/doing exactly the wrong thing at the time to shut up and let it be. The fun sucker is quite notorious, you probably know one. They are easily identified by the sudden awkward silences created after they try to be funny. There is no known cure for the fun sucker- they must come to terms with this and move on.