The common misspelling of "
Spider-Man".
Since this was mentioned in an episode of "Seinfeld" (where Jerry says "
Spiderman" sounds like a Jewishname), it may have helped spread the misspelling.
NOTE: the
hyphen "-" was put into the title/name to help distinguish "Spider-Man" from "Superman" on the comic book covers.
I was reading the a review of the latest
Spider-Man comic and the idiot editor spelled it "
Spiderman".
Pfft.