Ok, followup: cat is fine. She had to stay at the hospital overnight with IV fluids to flush out her system. Also, anyone who understands how picky cats are about what they eat would be surprised that a cat would even consider chocolate food... including the emergency vet, who had never seen a case of a cat eating chocolate in her entire 15 years, simply because cats are not supposed to be dumb enough to try eating it. She had also left said bowl of chocolates (which was up on a high shelf) alone for about three months already, so I had no reason to think she would go after it. Needless to say, I now keep all food items out of reach and sight, regardless of what they are. Since the incident, some of her favorite foods I have discovered (that I mostly try desperately to keep her from eating): tomatoes, peanuts, ice cream, raw sugar snap peas (and other veggies), hair, cardboard, string, rubber bands, and cat litter. The best part? After all that, she doesn't believe that kitty treat tuna flakes are food. Too much like paper...?