Killer is an ironic pet name — almost always given to the smallest, gentlest, or most harmless dog in the room. It's part of a long tradition of naming pets in deliberate contrast to their actual nature, alongside Beast and Brutus when applied to tiny dogs. The gap between the name and the animal is the joke.
The Irony Naming Tradition
Ironic names require the observer to understand that they're ironic — Killer only works as a name when it's visibly wrong for the dog. A Chihuahua named Killer is funny. A Rottweiler named Killer is something else entirely, and most owners making this choice are aware of the distinction. The name signals owner humor and a certain confidence about the dog's actual temperament.
Cultural Appearances
Killer appears as a pet name in film and TV, usually in the comedic tradition: a small, yappy dog with an outsized name. The name also appears in serious contexts for large working dogs whose owners mean it literally. Both traditions sit in uneasy adjacency in the registry.
The Counter-Reading: Registration Complications
Owners naming dogs Killer should know it can occasionally create friction at boarding facilities or veterinary offices where staff encounter the name without context. Most manage with a quick explanation about the dog's actual size and temperament.