Will My 65 Pound Dog Die From Eating A Piece Of Chocolate?

It depends how much And how your dog acts if it acts more nonactive or if it is whining You might wanna call a vet. If its a small square piece of chocolate probably  no but if it's the whole bar of chocolate maybe.

Obviously, you know chocolate is toxic to dogs or you would not be concerned enough to ask this question. Luckily for you, your dog is a bigger size, but it depends on how much chocolate he ate. One or two M&M's probably isn't worth worrying about, but anything more than that should be a concern. You should call your vet RIGHT NOW and ask them what you should do. They may direct you to an emergency vet phone number, and if so, call them. They may want you to pour hydrogen peroxide down your dogs throat. This will encourage him to vomit up the chocolate. Regardless, it sounds like you should refer to a veterinarian. Good luck to you and your dog.

Probably, it will get a terrifying case of heart worms.

OK "Guest" I don't think that was the right thing to say. Heart worms is not caused by chocolate.