I'm good with spiders and snakes, and
pet rats (mostly), but wild rats are definite nightmare fuel for me.
When I was little we watched a documentary on hantavirus which was creepy enough, and then there's all the historical fear of plagues which one of my history teachers casually mentioned was mostly spread via flea bites, and that rats were often carriers, and even it wasn't true it just piled right onto that fear-center in the back of my hindbrain.
But what really cemented it?
Er.
I'm going to spoiler this, because it's definitely nightmarish.
Spoiler
Talking to a mortuary assistant whose favorite debate was whether it was harder to cover up rat damage or cat damage on human corpses.
Apparently the cats will eat a human slower, because the rats will sort of call in other rats and they'll swarm a corpse and eat it down pretty fast, but a cat will guard the kill more. Also according to him, cats will often start up near the face but the rats will go straight for the guts, which is easier to hide. So he would go back and forth.
And then I made the mistake of getting drunk once at a bachelorette party when I was sitting next to an ER worker, and mentioning my nightmares about this.... and ended up listening to all the times she'd treat transients for injuries that were rats feeding on them, if they'd taken the wrong thing (apparently they always blamed "being drunk" even if it was clearly a stronger drug) and passed out in the wrong place.
She says they treat cat scratches more, but she'd never seen a cat actually try to eat a living human, and she'd treated plenty of people that rats had tried to eat while they were still alive.
She also talked about dogs, but it's usually really clearly the human owner/trainer's fault when it's dogs, and not so much the animals (with rare exceptions), so that one fortunately didn't add new nightmares.
And for whatever reason, I'm good with cats. I know they can be psychopathic sadistic monsters, but I'm good with them. *shrug*
So. Y'know.
Definitely afraid of rats.
(I try
really hard to make an exception for pet rats. It mostly works.)