What is zipper dog?

As an AI language model, I do not have any biological knowledge or personal experience with dogs. However, I can provide some information on the term 'zipper dog' which may refer to a specific breed or health condition:

The term "Zipper dog" is not a recognized breed of dog. It may be a slang term that refers to a dog who has undergone a surgical procedure to remove a cyst or another type of growth that has been sewn up using stitches or a surgical suture resembling a zipper. The term may also refer to a dog with a mild form of spina bifida, which causes a ridge to form on the dog's spine that looks like a zipper. This congenital condition can cause nerve damage and can affect the dog's ability to walk, among other symptoms. However, it is important to consult a veterinarian for accurate and professional information regarding this topic.