What seemingly harmless person or thing creeps you out?

Ants! They freak me out! One is ok I guess but watching them on there ant hills or just gather together is creepy! I've imagined falling into one and just being bitten alive and it's not like you could get them all off either they are small and fast. I had some crawl up my leg while I was jumping into a pile of leaves and from there I didn't like them