Mystery Art: Squid eats Ship

Around San Francisco (and other places, I'm sure - I'm not egotistical enough about my city to think this idea is particularly SF-based) I've seen many different small artworks stenciled and spray painted onto patches of sidewalk. One of my favorites that I've seen lately is a giant squid attacking what looks like a pirate ship:

So, two things:

First, does anyone know who did this? It's great.

Second, how hard do you think it would be to get away with doing one's own stencil-art on government property-aka-sidewalks? I mean, purely for curiosity's sake, of course. Cough.

PS - The small heart on the ship reminds me of another image I've seen, which is a pirate ship with a heart on its sails. Could it be the same stencil-artist? Oh I do hope so! I'm street-art geeking out at making that connection.