http://en.wikipedia.org/wiki/Arm_Fall_Off_Boy
Summary: A joke character with a similar name existed in comics fandom. The writer who put this character in the comic book mistakenly thought he was a preexisting character, and it's possible he confused him with the character who had the similar name.
The Wikipedia article is allowed to mention none of this because it assumes that reliable sources are professionally published and we can't use fanzines and blogs for information... and professionally publishing anything about a joke character whose superpower is that his arm falls off is not too likely.
(Also, previous example: http://en.wikipedia.org/wiki/Marion_Zimmer_Bradley . Bradley had a dispute with a fan writer over "fan fiction" (whether it even counts as fan fiction is highly questionable). The fan's side of this dispute is available in blogs and fan sources; Bradley, being a published writer, could get her side described in sources that are reliable by Wikipedia standards. Therefore, Wikipedia only tells one side of the story.)