Face of Boe

Someone please explain to me how this beautiful, otherworldly, cheeky creature:

Becomes this notsobeautiful, otherworldly, wise beyond recognition entity:

I just remember my reaction at the end of the episode (which one was it? I just remember Martha being there, so that must have been Series 3) when Jack tells them that they used to call him "the face of Boe" when he was younger and literally leaping off of the couch and being like "FUCKING AYE! WOT?! WOT?! NO WAY!" while my sister stared at me blankly (she had walked in in the middle of the episode, so she had no idea wot I was on about). I still forget every once in a while, probably because it hasn't been brought up since, but it never fails to blow my mind once I remember.
          Sort of like how realizing that "Torchwood" is an anagram of "Doctor Who," or that the drumming the Master heard was actually the heartbeat of a Time Lord, or how you can hear that same rhythm in th background of the theme song. All those things that are interwoven so well into the very essence of the show that they seem natural and unplanned. But we all know that Davies and Moffat knew/know exactly wot they're doing. Damn those creative, frightening minds.