@Stu my wife recently cost me a few sanity points by alerting me to some fascinating real world cyclopean horrors which might be of use for your Murmurs campaign...
Just down the street from us apparently live two fascinating insects:
1) "Velvet ants", which are actually a species of wasp which is capable of screaming
2) Solifugid which are described in the article as "an arachnid that makes up a whole category by itself, as it is neither a spider nor a scorpion". If you're "neither a spider nor a scorpion" you are clearly horriffic.
I'd also be curious to have people weigh in with other fascinating real-world florae and faunae which are inspiration for sci-fi/fantasy/horror. Such as: Wild Teak, trees which bleed when you cut into them.