OK, thanks for the information.
Vomiting usually gets a maximum of 60-70% of what is in the stomach
out, which means Z likely still has some fudge in there. In smaller doses, it just causes some gastrointestinal irritation, i.e. vomiting and maybe some diarrhea tomorrow. As long as this is all you see and he is otherwise eating, drinking, and acting normally, you shouldn't see any further problems.
In larger amounts, it starts to cause the heart to race and overexcitement/anxiety. This is a sign that he may need to be seen by an emergency vet tonight because it can result in fatal abnormal heart rhythms. By the time tremors start, if seen, the situation can rapidly progress to seizures
so it is paramount to have him seen if you notice that his heart is racing or he is overanxious/overexcited.
Monitor Jazmine for similar problems. The advantage for both is that they are bigger dogs, so it will take more chocolate to case a toxicity.
Please let me know if you need any more information!1