A dog collar having some form of spikes on it is nothing new. However, it is sometimes the case that the collar with spikes is used by some people to promote the idea that their dog is to be avoided at all costs. But then, that is not the reason as to why the dog collar with spikes was invented in the first place.
To get to the origins, we need to go back in time to Ancient Greece because, as it turns out, these spikes had a more plausible explanation for their appearance. In fact, the spikes were put onto the collars not to scare people or other dogs away, but to actually protect the dog.
The idea was that these spikes would protect the neck of a dog that was forced to stay outside all evening in order to protect the flock of sheep for the owner. The main reason why they had to be protected was because of the existence of wolves. However, a trained dog is going to be no match for the wolf, so it was decided to put spikes on the collar to offer protection to the neck as that is where the wolf would aim if they were attacking the dog.
Since then, the idea has just stuck around even though most people today are just not aware of the actual reason as to why this idea exists in the first place.