Some people already said it all … CENTIPEDES.
Spiders? A-ok. Snakes? No worries. Scorpios? They've got their charm.
But centipedes with their 177 pairs of legs, not even 100 (100 would have been bearable), slowly undulating across your calf during a warm summer morning. Urgh. And the fact they made a horror movie called The Human Centipede, though there were only three humans which means only 12 legs, makes it all the worse.
That and silver fish. Now silver fish are not that scary, but they are everywhere and the sheer number of them that I must have eaten in my lifetime makes me wonder how I haven't died from sepsis by now.