My boyfriend is petrified of roaches and spiders and after spending over three years with him I have started to share these fears (who knows why, I'm like a sponge I pick up these things) but I'd have to say a roach would be worse.
I would look at them all day long, but I don't want them ON me. I was expecting to see snakes mentioned here too! I love snakes I have a ball python right now, but I've had a few corn snakes and others in the past.
Well, I've kept both as pets, so neither of these would scare me, but there are tons of other things that would so none of these options really fit me.
Cockroach would scare me more cause I'm extremely grossed out by them I would not want one on me. Although I am also scared of spiders, I find tarantulas to be a lot less threatening than most.
Neither of them scare me, because I'd have no issue killing either of them. What does scare me is thunder....I know it's silly but it's always freaked me out.
Both of these scary creatures are nothing in comparison to jellyfish. I hate and fear those brainless blobs and am positive I would not want one on my arm.