Regarding pubic lice, and human lice in general, the research using lice to inform knowledge of human evolution is, i think, facinating. Just couple quick links - https://www.livescience.com/41028-lice-reveal-clues-to-human-evolution.html; https://www.pbs.org/wgbh/nova/video/lice-and-human-evolution/
But for me, the North American Jerusalem cricket. I don’t know what it is about them, but, ugh.