Okay, maybe not Banksy exactly, but when I was four I drew Rudolph the Red Nosed Reindeer on my bedroom wall. Not his whole body -- just his head peering around the dresser. Still, I caught hell for it.
I didn't pull that stunt again until I was at THE X-FILES. I was on the third season staff (known to some as the beloved, golden, Darin Morgan season) and the writers' offices were in a little building on the FOX lot. I would sit at my desk and stare at the wall across from me as I pondered what I would write next. The ceilings were pretty high and there was a lot of empty wall to stare at -- so one day I grabbed a marker and drew an alien head peering over the door in the wall (the series overarching story dealt with extra-terrestrials). A week later I drew another head, one that pertained to the second episode of our unfolding season. Then I drew a third -- and soon I was on a season-long mission, drawing an alien to reflect each new episode as it was written. Late in the year the creator of the show Chris Carter came by the offices and saw the graffitied wall and after a long moment remarked, "Cool." Way better than, "Drawing on the walls? Your fired."
If you're familiar with the season it's fun to see which drawing represents which episode. Sadly this photo was taken before the last couple episodes were written, hence their absence. (FYI: The camera flash sorta obscures the one alien reading an X-Files comic as he's being struck by lightning.)