Them need to die. It's me or them.
When I was a teenager we were out on a small sailing boat and moored at some island for the night. I woke up to one of my friends screaming. Spiders everywhere. A spider horde. Humans panic -> spiders bite. They were small but they were with many. The bites weren't excruciatingly painful but they were painful enough to be annoying, and they itched like hell at the same time. Ever since then I've been arachnophobic.
I still wake up in a panic sometimes having had a bad dream of some horde of creepy crawlers crawling all over me, or worse, of a giant spider (imagine a Skyrim spider or bigger) hunting me trying to have me for lunch.
Imagine my horror when watching LotR, or playing Skyrim.
I would drop my gun, run in any random direction, and call for air support.