This is the result of a search for "finger" on Commons, requesting file type GIF; the user was apparently hoping to find an image of someone "giving the finger":
https://commons.wikimedia.org/w/index.php?search=finger&title=Special:MediaSearch&go=Go&type=image&filemime=gif
(WARNING: THE ABOVE LINK GIVES A HIGHLY NSFW RESULT)
I don't know what is going on behind the scenes here, but an innocuous search term should not result in displaying a set of sexually explicit videos. It seems to me that this is an inappropriate enough result that it should be treated on the same priority as a bug.