What The Hell Is An Ocarina?

I was in my office this morning listening to 99X and Puff played one of my favorite AC/DC songs, "It's A Long Way To The Top (If You Wanna Rock 'N' Roll)."  What sets the song apart from all other AC/DC songs is the bridge that features bagpipes.  Now AC/DC is Australian, so I have no idea how they got the inspiration to use a Scottish musical instrument.  But it got me to thinking--What other weird instruments have been used in Rock music over the years?  Well, there's actually a list.  And it's topped by one of the SBC's favorites.  Don't you just love the Internet?