The ultimate troll entry for me on Snopes is:
> So how did this claim arise? In a 1993 PC Professional article, columnist Lisa Holst wrote about the ubiquitous lists of “facts” that were circulating via e-mail and how readily they were accepted as truthful by gullible recipients. To demonstrate her point, Holst offered her own made-up list of equally ridiculous “facts,” among which was the statistic cited above about the average person’s swallowing eight spiders per year, which she took from a collection of common misbeliefs printed in a 1954 book on insect folklore. In a delicious irony, Holst’s propagation of this false “fact” has spurred it into becoming one of the most widely-circulated bits of misinformation to be found on the Internet.
This is NOT in their "TroLL" section -- it is not clearly marked as being a fake fact.
See https://www.snopes.com/fact-check/swallow-spiders/ .
Yet if you do the homework -- other people have, and I have tried to reproduce it myself -- there is no such source. See https://skeptics.stackexchange.com/questions/2094/is-a-write... for example.
This Snopes article cites a column reportedly called "Reading Is Believing" from a periodical called "PC Professional", page 71, date 7 January 1993. I was unable to find the existence of any such periodical although there is "PC professionnel", published in German, ISSN 0939-5822, whose archives seem to only be available in German libraries (and I have not reviewed those).
However, I was able to find in the Cornell University archives, a quarterly periodical called the Cornell Engineer, which carried a column by a student columnist dated April 1992 (Volume 56 number 2, page 24, column title "Stress and Strain", author Margot Anne-Stephanie Vigeant '94). That seems to predate the January 1993 citation given in the Snopes article, and the 1992 student-publication column text says in part
> My first topic for this issue is worries. I've decided that there are just too many well adjusted, un-paranoid people in this school (NOT), so I've decided to wreck their peace of mind by sharing a list of my favorite worries with them. These are the kind of things that just jump into your mind right before you're about to fall asleep - horrible little night gremlins whose goal it is to keep you up just a little bit longer. So here they are, hope you can sleep after this:
> The average person swallows eight spiders while sleeping, in their lifetime. What if all eight show up tonight?
Meanwhile the source that Snopes apparently made up, Lisa Birgit Holst, is an anagram for "This is a big troll".
It's just odd. Their debunking contains a pointless lie; there is a real citation available they chose not to use.