My neighbor shoot a deer several years ago with a 3" slug, aiming for the neck. When he walked up to the deer, he poked it with his shotgun and it didn't move. Then, when he looked at the face, he noticed the deer's eyes were closed. He had heard many years earlier that if they eyes were closed, the deer may still be alive. He took his knife, cut the esophagus, and the deer bayed it's last breath.
When we all met up back at the trucks, we found that his bullet had heavily grazed the side of the deer's head, knocking it out, but not killing it.