A giant imaginary hedgehog from the Monty Python mockumentary skit "The Piranha Brothers" in which gangster Dinsdale Piranha believes he's being watched by same.
Dinsdale was a perfectly normal person in every way, except in as much as he was convinced that he was being watched by a giant hedgehog whom he referred to as Spiny Norman.
A low-key term for a mud shark. Best used in circles where the term "mud shark" is already too well known.
Friend 1: "Hey did you know Natalie is having a kid with her pimp?"
Friend 2: "She's quite the spiny dogfish that one. I knew she would end up a baby-momma sooner or later."
