A Mogwai of a Different Stripe
Stripe puts the nature vs. nurture argument to bed, at least in regards to the cuddly mogwai species. Stripe is born evil. When still a cuddly mogwai, he's cute, but 100% devious. Billy's friend Pete wants to take Stripe home, and he admires Stripe's unique appearance:
PETE: Hey, look, that one's got a cute little stripe on its head.
Then Stripe bites him. Yeowch.
From there, Stripe ties up the dog, tricks Billy into feeding him after midnight, and then evolves from fuzzy and mean, like an ill-tempered Chihuahua, into a cold-blooded murdering machine. Spike, and the other mutated gremlins, are responsible for killing multiple people, blowing up cars, and getting popcorn all over the floor at the movie theater.
In the bar, we see the gremlins drink beer from the tap, smoke, flash Kate, play croquet on pool tables, gamble at poker, and shoot at humans and each other with guns. And we haven't even gotten to the one who's wearing leg warmers.
Stripe is evil incarnate, making him an antagonist who's easy to root against. But consider this. Stripe hatched from Gizmo. In the weird world of mogwai asexual reproduction, Gizmo is still Stripe's father. Could Gizmo be responsible for his terrible son? Maybe Gizmo's absentee parenting is to blame.