Gracie McCoy is a mom to a blind son and a huge but generally gentle Great Dane named Dubai.
But the dog clearly is a loyal member of the family as evidenced by the appearance of an unwanted man who came into her front door.
The man stopped to pet the dog and when McCoy heard anotjher unfamiliar voice she yelled. Her blind son had no idea what was going on. But Dubai took matters into his own hands. Or teeth.