A Thestral is a breed of winged horses with a skeletal body, face with reptilian features, and wide, leathery wings that resemble a bat's. They are very rare, and are considered dangerous by the Ministry of Magic.
A dog collar is a piece of material put around the neck of a dog. A collar may be used for control, identification, fashion, or other purposes. Identification tags and medical information are often placed on dog collars. Collars are also useful for controlling a dog manually, as they provide a handle for grabbing.
It's good to be sure how your dog feels when you hug him or her, and how he feels when strangers go in for a hug, especially since hugs mean putting your face next to a sharp set of teeth. If a dog barely tolerates hugs, then the wrong hug at the wrong time could mean the dog snaps at the hugger.