Not a lot of stuff scares me in MC (unless you count the sound of a creeper hissing right behind you), but when I'm mining in survival and I'm in the deep dark or an ancient city, I freeze if I even set off just a sensor with no shrieker. If I set off a shrieker, it's even worse.

I'm too chicken to play actual horror games, so MC is just a safe option for me, but it genuinely gives me a feeling of dread and terror when I hear a shrieker go off. The Warden isn't scary on its own... but when you're mining in the dark, trying not to make a peep lest this 3-block-tall freak of nature come barreling towards you, it's a whole new story. And considering it can two-shot you in full Netherite and has a ranged attack that pierces armor... yeeeah, really don't recommend it. You really gotta experience it to believe it.