Foreign bodies can do one of two things in a dog: either stick to food and get out of the body (through feces) or get stuck to the intestinal wall, and require surgery.
If this just happened, take your dog to the veterinary emergency asap, and have them work on it. Sometimes they can grab the item with a endoscope while it is still in the stomach. Once it digests to the intestines, you either wait, or get surgery. (Then it is a 50/50 shot that it will come out.)
I would take the dog to the vet immediately, the dog could have very serious internal damage from eating the nail. The vets might be able to help your dog.
Also, you should keep nails - and the likes - so that animals and children can not get to it. Keep it out of their reach.
It will create a rift in the space/time continuum, but the dog will not notice since their perception of time is different than ours.
if a dog eats ants its perfectly fine dogs eat everything
the dog eats poo
Poop
Not much unless he eats too much.
certain death.
The duck will get sick
He won't digest it and it may make it sick.
you should call a vet
it is an overdose, it can give your dog an infection internaly, dont do it
you have to rush it to the closest hospital or vet
Nothing. They are harmless.
if he/she doesnt have any health problems, nothing should happen.