INT. AIRPLANE
Rand is eating his airline dinner. He's looking out the window. Thinking. An Oriental stewardess walks up.
STEWARDESS
More coffee?
Rand nods. The stewardess fills his cup. Rand looks at her.
RAND
Ever heard of "Mogwai"?
She nods.
RAND
What does it mean?
She gives Rand his coffee.
STEWARDESS
Devil.*
Here's why I love this:
I remember that as a little kid I was fascinated by the mogwai–gremlin metamorphosis and got stuck on one big question, even wrote stories trying to answer it: If Gizmo ate something after midnight (I mean, he wouldn't, he didn't, but if he did somehow, like if you tricked him or forced him to), would the gremlin he turned into be evil like the others?—because all his offspring† are nasty even before they become gremlins. The difference between Gizmo and the gremlins isn't just that he never transforms, but that he's always sweet and nice and they're always mischievous and nasty...always, even before they go into their cocoons.
So is Gizmo just an anomalously gentle mogwai?—or is it somehow always true that the offspring are nastier than the parent? Are you not supposed to get them wet just because wetness leads to more mogwai and mogwai can be dangerous, or are you not supposed to make them wet because the reproductive process, like sound deterioration when copying tapes (remember copying tapes?), results in a kind of moral degradation...?
What's exciting about this (possibly) first draft of Gremlins is that it provides an answer—both an in-story answer and a kind of a meta-answer.

Mogwai most certainly for sale, in that first draft.
The "in-story answer":
Mogwai are just fucking bad news. Whether Gizmo's a freak or is just, like, the unique decent father of all mogwai goes unanswered, but we do know this: mogwai are little devils, and dangerous, and trouble, and the main difference between mogwai and gremlins isn't that mogwai are sweet and gremlins are evil, but that mogwai look cute and gremlins look evil.
That old draft of Gremlins is a much darker script than what wound up being filmed years later.‡ For one thing, the gremlins basically eat everything, people included. For example, instead of tying up Billy's dog with Christmas lights, they eat him—tear him to shreds—and this is when they're still mogwai!
In fact, that original Gremlins is maybe most notable for the fact that there is no Gizmo. Billy gets a mogwai from his dad, Billy hates the mogwai, the mogwai reproduces...and then there is no longer any effort to distinguish one from the others: no Stripe, no Gizmo, just a mess of mogwai who then become a mess of gremlins.
And this leads us to...
The "meta-answer":
Whence Gizmo? Whether this was an order from a studio or just a clever idea that Chris Columbus came up with on his own, the sweet mogwai is clearly a plot device added in later to achieve certain goals, including (presumably) the lightening-up of a super-dark story and the introduction of a sort of...plot...foothold? (Terminology: always a weakness for me.)
I'm reminded of
that story about the original
Transformers movie: how cynical corporate interests accidentally resulted in a sort of amazing plot choice.
Gremlins would not be nearly so good if there weren't the contrast between Gizmo and the others; indeed, as I was just saying, half of my interest in the thing as a kid was speculation about what went wrong, where they went bad, whether Gizmo was corruptible, and so forth.
But so apparently the answer—I mean, the meta-answer—to my boyhood questions is: mogwai are evil, and the reason Gizmo isn't evil is that he got written in that way.
In other words—contrary to the chronology of the plot—gremlins came first; Gizmo came second.

Gizmo would never do such a thing...would he?
Three other things
(possibly interesting only to writers and rewriters):
1. In both drafts, the creatures are called mogwai throughout—before and after their metamorphosis. The script refers to them as gremlins only implicitly, in the title. (Obviously this doesn't stop me from continuing to call the reptilian ones gremlins and the mammalian ones mogwai. I don't give a fuck.)
2. The three rules—so central and iconic—seem to have come only at the very end. The 1981 draft has only one rule, about light, and by the seventh draft we've already got the eating-after-midnight rule (I may have read too carelessly, but I think originally they just plain metamorphosed: no rule-breaking or food connection at all!)—but the bit about water is just something Billy discovers on his own, not a rule!
3. By that seventh draft, Gremlins is pretty much Gremlins as we know and love it—except that at the end (I can barely bear to share this with you, it makes me so uncomfortable) Gizmo sprouts wings and flies off like a beautiful butterfly leaving behind a trail of fairy dust. I'M SERIOUS.§
In conclusion...
I still sort of want to know what Gizmo would be like as a gremlin. And that's one to grow on.

This actually I can sort of see Gizmo doing.
* Forgive the nonstandard formatting; can't be bothered to approximate the right way on Blogger.
† Most of the gremlins in the movie are descended directly from Stripe (and presumably his own offspring) in the pool at the YMCA and start right out as gremlins, but the first batch of them start out as mogwai and pop out of Gizmo's wet back. Billy and his mom—mainly his mom—kill all Gizmo's original offspring except Stripe; when Billy's hunting Stripe, pre–swimming pool, there is another gremlin out there—the one from the school, Gizmo's grandkid—but presumably he winds up in the movie theater with the rest of them; no need to worry. (NOTE: In that 1981 draft, Billy's mom doesn't kill all those gremlins [in that amazing sequence with the blender, the microwave, etc.]. No: they kill her. And the dad. Then they throw their severed heads at Billy. True story!)
‡ Cates Kate's Christmas story makes a lot more sense in this first draft. Interestingly, in both the 1981 script and the 1983 script, the story belongs to someone other than Kate; the 1981 script gives it to Dorry, the owner of the bar, and the 1983 script gives it to Gerald, the Judge Reinhold character. It just kept getting moved around. (To be fair, it is a weirdly amazing story.)
§ You can almost read this as a super-cynical fuck-you gesture, satirizing the very concept of Gizmo: keeping in mind that Gizmo was added later, might Columbus have been saying, "Yeah, this angelic mogwai, mogwai meaning devil, remember...since he's here, he might as well transmogrify into some goddamned magical Disney character." (Interestingly, that 1981 draft describes the mogwai as being cuter than any Disney character...but that one ate dog instestines and laughed.)