What freaks you out the most?

I’m just curious about what some of the options are. I know someone will say Frostbite spiders (which valid). For me, it’s going underwater. I’m okay if it is in rivers or not very deep lakes but I found an underwater shipwreck somewhere off the coast nearish Winterhold and I noped out of there. It was waaaay too deep for me. Something about seeing absolutely nothing around my character but cloudy water is just shudders

Edit: It’s called Pilgrim’s Trench if anyone wants to go for it. You especially need waterbreathing to reach it. Or be an Argonian.