I have a severe fear of octopi and squids. I tried looking up "cephalopod phobia" but that's apparently not a thing, but I did find something called "chapodiphobia" which is only the fear of octopi, no squids. I have no idea what it is about them that makes them creepy to me, maybe the fact that I can't swim doesn't help but I'm not scared of everything in the water, so I don't fully understand it myself. I can even remember one time seeing a picture of a squid and straight up throwing my laptop to the other side of my room in a panic.
You'd think it'd be pretty uncommon to even see them without actively going out of your way to look up images of them, but let me tell you, the sheer amount of times I've seen an octopus in a movie, tv show, or advert, is insane. There's even a British company called "Octopus Energy" which shows up on tv from time to time