It is Impossible

[Necronomicon II]

Penis monsters are beautiful, though. 

[Biomechanoid]

Penis monsters are beautiful, though. 

Lieutenant Eckhardt: "Where you been spending your nights?"

A shark is a known quantity, they're still terrifying. The unknown that's scary is more where is it, when will it strike, how will it strike. Whether it's an ancient elder god or a robot's science experiment is secondary.

Okay, jokes aside. This describes best how I felt in my first viewing of Alien. When Ripley was in the corridors preparing to escape in the shuttle, every single moment I was on the edge of my seat teeming with dread - yet it never appeared. Weaver also was very convincing in portraying that dread. The "no-show" was more frightening than if it actually did appear in the corridors at that time.

It's similar to my first viewing of The Exorcist. Certainly some scary visuals, but I felt the most dread when they simply showed Regan's bedroom closed door. They did that multiple times. Each time I felt, "just don't open the door!"

[Immortan Jonesy]

A shark is a known quantity, they're still terrifying. The unknown that's scary is more where is it, when will it strike, how will it strike. Whether it's an ancient elder god or a robot's science experiment is secondary.

I don't agree entirely but yeah, the way you handle the creature is very important. The last prequel provides a good example of this, since
the Alien shows almost the same behavior as the Neomorph.

[The Old One]

Penis monsters are beautiful, though. 

Lieutenant Eckhardt: "Where you been spending your nights?"

Why, Biomechanoid-

You ought to think about the future.

[SiL]

When a big component of that fear of the unknown is not knowing what you might find out in the scary blackness of space, and that anyone might find crazy penis monsters capable of anything, it undercuts that horror when you learn that said penis monsters are only 20 years old at best and limited in scope to only the places a deranged robot has visited.

The scariest part is still it crawling around trying to eat your face.

Sharks are still scary even if you know you just need to stay out of the water.

[Xenomrph]

When a big component of that fear of the unknown is not knowing what you might find out in the scary blackness of space, and that anyone might find crazy penis monsters capable of anything, it undercuts that horror when you learn that said penis monsters are only 20 years old at best and limited in scope to only the places a deranged robot has visited.

The scariest part is still it crawling around trying to eat your face.

Sharks are still scary even if you know you just need to stay out of the water.

The shark gets less scary if you know with certainty that it isn't going to be present in 99.997% of the water you go into, though.

[SiL]

The shark gets less scary if you know with certainty that it isn't going to be present in 99.997% of the water you go into, though.

The Alien was delegated to one ship on one planetoid for three movies and one ship in our solar system for another movie. That didn't affect two of them being scary and didn't make the other two not scary.

Besides which, no -- it not being in 99.97% of whatever doesn't make it any less scary when it's coming right for you. It's not about how scary the chances of randomly finding it are, it's about how scary it is if you do find it.

[Necronomicon II]

If David made a shark more penis-y does that make it man-made? 

[Immortan Jonesy]

When a big component of that fear of the unknown is not knowing what you might find out in the scary blackness of space, and that anyone might find crazy penis monsters capable of anything, it undercuts that horror when you learn that said penis monsters are only 20 years old at best and limited in scope to only the places a deranged robot has visited.

The scariest part is still it crawling around trying to eat your face.

Sharks are still scary even if you know you just need to stay out of the water.

I think the scariest part is the creepiness of the Alien, and here is where I find the skull inside the dome quite helpful: that subtle humanness present in the monster is successful in creating an uncanny valley effect. Is to be looking at the soul of a person being imprisoned inside this psycho-sexual nightmare. It almost looks like a science fiction metaphor about hell; with a fragment of human consciousness being tortured after death.

Also, the fear of unknown is still a better thing for horror movies in my opinion. The vagueness and ambiguity of a potential threat can trigger irrational fears. Why do you think some people are frightened by clowns or masked guys? because masks can hide a person's true emotions, so you can not know if that person is a threat or not. Some people find that scary. There is definitely an eerie feeling when you're facing a threat of mysterious nature.

[SiL]

You're not scared by not knowing what city the clown was born in, though. Not knowing their intent makes you anxious and afraid.

Same with the Alien. Exactly what planet it came from, where and when is utterly secondary -- if that -- to "it may or may not be in the room with me right now and try to murder me horribly."

We're not scared by the uncertainty of origin, we're scared by the uncertainty of its presence -- whether that's the uncertainty of whether it is present, or the uncertainty of what it will do while present.

Don't get me wrong, I'm fully on board the "I'd rather not have an answer" train -- but knowing the origin of the Alien doesn't make it more or less scary. What it does in a given circumstance, however, does.

[Immortan Jonesy]

That is why I've said "There is definitely an eerie feeling when you're facing a threat of mysterious nature." I'm not exclusively talking about origins, but about behaviour. I think someone said something
similar:

In Alien we're hearing that something horrible is happening to Lambert, but Scott never show us the full picture of what's going on.

[Huggs]

What about scary clown penis?

[The Old One]

Is clown penis ever not scary?

[TheSailingRabbit]

What about scary clown penis?

Pennywise meets Alien.

[Immortan Jonesy]

What about scary clown penis?

You mean President Trump's penis?