The danger of corn on the cob isn't necessarily the corn itself; it's the cob that's the problem. The cob is difficult to digest, meaning it will get lodged in your pet's small intestine and cause intestinal obstruction - which is potentially fatal without surgery. Also, while the corn itself isn't toxic, too much of it can cause problem in the digestive tract which can lead to pain, vomiting and lethargy.
This one probably goes without saying, but never ever, ever, ever feed your dog chocolate! Though the caffeine is certainly detrimental to a dog's health, chocolate also contains toxins known as theobromine which cause vomiting, diarrhea and fatal damage to your dog's heart and nervous system. The darker the chocolate, the more likely it is to cause severe, if not fatal, issues. Just don't do it!
The information in this article was vetted by Dr. Robert L. Proietto, VMD, MS.