If you want to make a monster sympathetic, give it fur.  Fur is the dividing line between a monster you can feel a little empathy for and one that you want to see die.

It’s not an exact science.  E.T. was bald, but then again, he wasn’t a monster.  He was just a little lost guy from outer space.  If an alien or otherwise bizarre creature is in your story and doesn’t eat anyone, their fur (or lack thereof) is less important.

In the classic film Alien, a ruthless predator kills the crew, one-by-one.  Sure, the xenomorph is terrifying from top-to-bottom.  Its reproduction method, its acid blood, that weird little mouth that pops out of its bigger mouth, these are all things designed to make it a strange, unearthly beastie.  But when you get right down to it, the xenomorph is just an animal.  It isn’t malicious.  It’s just doing what comes naturally.

Our visceral reaction to the xeno changes though when you replace it with a tiger.  If somehow a great cat got loose on the Nostromo and did the exact same thing as the xenomorph, we’d be far less likely to rejoice with its death.  True, tigers don’t have acid blood, but the end result is the same.  Both are predators.  One just has a little more cuddle factor.

Sully from Monsters, Inc, is a fuzzy good guy.  Randal, his chief rival, is the bald bad guy.  But, in fairness, the monsters in the movie come in dozens of different varieties, and most of the bald ones are presented as likeable and friendly.  So kudos to you, Pixar, for breaking the fuzzy barrier.

The cuddle factor applies to terrestrial animals just as well as fictional ones.  It’s why there are (roughly estimating) 1000 more killer shark movies than any other animal.  It’s not the teeth or the cold dead eyes.  It’s the baldness.  Although I’m sure the teeth and the eyes don’t help anything.

Most horrifying cosmic monsters lack fur.  From Lovecraft’s Cthulhu to DC’s Starro the Conqueror to anything and everything in-between, you’d be hard pressed to find a thing from another dimension with fur or hair.  If Yog-Sothoth had a nice head of hair, we’d probably still fear him.  But we’d also relate to him better.

Even bald humans tend to get the short end of the stick.  Lex Luthor’s shiny pate stands as the polar opposite to Superman’s lush, black hair.  And if a guy gets blasted with radiation and mutates into a supergenius, you can almost always tell if he’s going to be good or bad by how much hair he retains on his giant head.  This isn’t quite as true as it used to be, as baldness acceptance has gained some traction.

But still, no sympathy for sharks or squids in sight.  Maybe scientists will breed a fur-bearing shark one day.  Until then, I guess they’re just out of luck.