What the F**k? Of Street Art, Dental Exams & Impossible Objects

This is by far the strangest - and most disturbing - street art I've ever seen. I've come across far more violent, grotesque etc, but nothing this surreal. I'm not versed in street tagging, but this is fu**ed up. I also couldn't find anything remotely close to it on the web. Where to begin? Well first off, there's the Escher 'impossible object' triangles; why are they 'centered' on the dental exam? Why use dentist's hands and implements in the first place? The '70s hair model doesn't look like she's being tortured, or in any discomfort at all really.

So what is this trying to be - or say? And why did the other taggers leave it so pristine? Is 'BUB ChBUB the creator of this abomination? Seriously any ideas and/or wild guesses would be much appreciated.

Update: Today I got a much closer look at this. It's actually been plastered to the wall like an old time circus poster, and there's a signature of sorts, the 'XD' in the upper right hand corner. Unfortunately I couldn't find anything new about it though...