Some monsters are brutes — formidable muscles with very little in the brain department. They are fearsome creatures because they cannot reason. Like a hungry shark, they are all appetite and no manners. Their thinking is straight ahead — hunt, kill, eat, sleep and repeat.
Monsters with minds are much scarier. A brute cannot plan more than a few moves into the future, a monster with a powerful brain and no moral compass is often one step ahead of a human. We are easily distracted. Love, lust, greed, ambition, and everything else under the sun, pull and push us in different directions.
Stories with brutish monsters seem to require monster hunters with divided loyalties, complicated romantic entanglements or other major distractions — while stories featuring brainy evil creatures the monster can be paired with less complicated heroes.
Of course the best monster stories have a matched pair — a clever beast and an equally smart heroic figure. Sherlock Holmes and Moriarty — in the original stories, classic films and current TV incarnations — are a perfectly matched pair. I recently read an article delineating just how far on the scale of psychopathology Sherlock sits. (Probably right next to his nemesis.) The Vampire Count and the good doctor, Van Helsing, are a matched pair in the original Bram Stoker tale, but in many retellings of the classic, things get out of balance.
Dr. Frankenstein and his creation are a team that inspires a wide range of stories and in the best versions it’s very hard to tell the monster from the “good” man. I’m a fan of Mary Shelley’s story. If you’ve never read it, you’ll be surprised by the ambivalence about good and evil. It may not have been Mary Shelley’s intention, but more often than not, I found myself on the brainy monster’s side.