Vacation: Or, how I learned to stop worrying and love San Francisco

I'll tell you why I'm learning to love this city:

Because in this random-ass store in North Beach you can (apparently) buy USED SKULLS. Used. Skulls. Cheaper/better than new skulls? How used are they, exactly? Human skulls, or more like cat/moose/monkey skulls? Can you buy them in bulk? How do I know these are quality skulls and not some cheap knock off?

Used. Skulls. 'Nuff said.