Ever since the show was brought back in 2005, the sonic screwdriver has been a main fixture in Doctor Who. The multi-tool with a million and one functions is almost as recognizable as the TARDIS, but it wasn't always his go to solution for a locked door or medical scan as it is today.The device first appeared during the run of the second Doctor, but it was slowly phased out before the series was brought back by Russell T. Davies. New functions have been revealed over the past few years, with River Song even introducing the "Red setting." It was originally taken away due to the fact that writers had a hard time writing stories where problems could not easily be solved with a quick wave of the device. Today's writers are a bit more creative and often find ways to neutralize the tool's effectiveness in order to make a story more compelling. Let's just hope it stays that way.