A muggin (AKA a pug-pin) is a cross between a miniature pinscher and a pug. They look somewhat like a miniature rottweiler, although the pug nose is more pronounced -- they are quite cute, although appearance and temperament can vary greatly. There is an attempt underway to create a formal muggin breed, the carlin pinscher. The carlin pinscher has been carefully bred to eliminate some breathing problems that appear in many pug mixes, are are fairly calm in temperament, although they do have some terrier traits, and are active and playful.
While muggins and carlin pinschers are both recognized by the American Canine Hybrid Club, neither are recognized by the American Kennel Club.