The Re-Deads from Ocarina of Time were all fine by me, I was 10 years old when I played that game for the first time, and I even had a few laughs everytime they attacked Link, it always looked like they were molesting him.
But Skullturas...
That noise they make... how they suddenly appear out of nowhere, those empty eye sockets one bigger that the other one.
The way they move, how sometimes 3 of them appear AT THE SAME TIME. They're invulnerable as long as they're facing you, but vulnerable once they turn their backs on you... but then you see this fleshy exposed skin, and you wonder what in the hell this thing truly is. It has legs just like a spider... but is it one? no. It the definition of horror to me, skullturas in whichever size they choose to appear, whenever they regular, gigantic, small or golden, they are all horrible to me. I can't even see a screenshot of those fuckers.
Funniest thing is, I don't even have arachnophobia.
Oh, and I played Amnesia, no biggie until my character started losing his sanity and then cockroaches started appearing on my monitor. I would've accepted spiders, worms, whatever... even a fucking screamer, but noooooooooo, the devs had to go with cockroaches, well fuck that I ain't playing that game anymore.