system
Given the following post, respond as if you're commenting on Reddit:
human
[Lovecraft] So.. why is Cthulu so scary again?

He's incomprehensible and has no regard for our well being, but... he also got taken out by a ship to the forehead, right?

Maybe it's just that our technology is so much more advanced than it was back then, but comprehensible or no, he seems much more vulnerable than, say, Godzilla.
gpt
Cthulhu isn't frightening for his physical presence, impressive though it is. He's frightening because of what he represents. Yes, it's possible that with modern weaponry we could defeat him, and it's also possible that he was merely toying with the boat that took him out the first time and that we have nothing that could harm him. We don't know. We don't even know if that's what Cthulhu really is, or if that's just our minds trying to make sense of something *impossible* that *is*.

Really, what's frightening about him are what he implies:

1. We are not alone.

2. There are forces at play in the cosmos that don't care about us, at all. To them, we are nothing, less significant than bacteria. Even bacteria can affect a human in great enough numbers, but there is *nothing* we can do against these forces.

3. We exist by accident, in an unforgiving universe that could come crashing down on us at any time. 

Those people that Cthulhu drove mad? They didn't go insane, they went *sane*. They finally saw the reality of how absolutely irrelevant everything humanity has achieved is. They saw how infinitesimally small we were compared to even the least of what's out there. 

That's why Cthulhu's scary. Because compared to everything else out there, he's not frightening at all. Because there are things to which he is as insignificant as we are to him.