A "spiked collar" refers to a type of collar worn by animals, typically dogs, that has sharp spikes attached to it. It is used as a decorative accessory or as a way to protect the animal and discourage others from getting too close. Full definition
Dogs wearing prong collars receive a much stronger bite during this type of play, while dogs wearing spiked collars can inflict injury. (pets.georgetown.org)
Pit Bulls are regularly marched around with spike collars as the ultimate in macho, and also regularly killed by animal shelters worried that the dogs may become aggressive at some later date. (pethelpful.com)
Glenn Robinson, the rookie forward with the Milwaukee Bucks, is often called Big Dog, and he has, on his right deltoid, a tattoo of a big dog — a pit bull in a red spiked collar. (si.com)