But after the X-ray revealed the knife, which extended upwards towards his throat, Kyle was prepared for surgery, which took about an hour to complete.
The six-month-old collie-Staffordshire Bull Terrier cross is recovering from major surgery to remove a 15-inch serrated knife from his stomach.
He was only 18 inches long and 18 inches tall when the knife was taken out.
Kyle's amazing brush with death only came to light after he was taken to a veterinary hospital in Leeds with a vomiting problem.
"It was only when it didn't settle down that we decided to do an X-ray. It was just amazing," she said.
"The knife could have cut his internal organs to shreds at any time and it's a miracle he survived."
Kyle's owner Eva Oliver, from Leeds, had taken the puppy to the hospital on New Year's Eve.
But after the X-ray revealed the knife, which extended upwards towards his throat, Kyle was prepared for surgery, which took about an hour to complete.
"They opened up the abdomen and approached the stomach," Dr Draper continued.
"They then opened up the stomach before removing the knife, handle first, being careful so that the blade didn't cut anything.
"Dogs eat things all the time but not things like this. I've been a vet for 15 years and I have never seen anything like this in a dog," she added.
Exactly how the puppy came to swallow the knife was a mystery.
Dr Draper added: "We saw the puppy last week. He had a little swelling after the surgery but he's been bouncing around and his eating is back to normal."