It looks like Wikia has now stooped to using unscrupulous advertisers that trap the user with JavaScript alerts and display faux dialog boxes to mislead the user into thinking they're "infected." Make the mistake of clicking a link to Wikia and you may be welcomed with this dialog box:
Regardless of what you click, you'll be whisked away (in the same browser tab) to this fake "system scan":
Attempting to click Back (to the Wikia page you were trying to view) will just cough up another JavaScript dialog; it seems Wikia is more interested in driving you to their advertisers than serving their actual user-generated content.
(Perhaps unsurprisingly, since the early pioneers of this scare-ware advertising, Bonzi.com, have enjoyed special protection from Jimmy Wales.)
Essentially, this means every link to Wikia on Wikipedia is a potential infection vector for this questionable software. (Anyone moderately savvy with computers shouldn't be fooled, of course... but would the mythical "child in Africa" be expected to tell the difference between an ad and a real OS dialog?)
If Wikipedia has any scruples, it should cease linking anywhere to Wikia-owned sites.