Hi there. My name is ***** ***** I'm happy to help you.
The toxicity of chocolate is judged by the amount of theobromine in it. Milk chocolate (like the kind in candy bars), contains 60 mg per ounce of theobromine. The toxic dose is one ounce of milk chocolate per pound of body weight. For example one pound of milk chocolate is poisonous to the nervous system of a 20-pound dog. If you figure it all out, it ends up being that it takes 2-3 chocolate bars to be toxic to a 10 pound dog.
Even cocoa powder, the kind in Oreos, at the amount Booyah got, isn't likely to cause any problems. I've seen dogs in clinic several times who ate whole packages of Oreos with no effects other than some vomiting and/or diarrhea.
Of course, it is always better to be safe than sorry, and the safest thing to do is to induce vomiting in your pup. Details on how to make that happen can be found here: http://www.petplace.com/dogs/how-to-induce-vomiting-emesis-in-dogs/page1.aspx
The best thing to do is give him some peroxide. Then adopt a watch and wait posture. The symptoms of chocolate toxicity include trembling, nervousness, shaking, increased heart rate, panting, and worse case scenario, seizures or death. Dogs that eat dark baker's chocolate squares are at most risk of seizing or dying from chocolate, but I don't expect that to be a problem here with Booyah.
I hope this helps.