Bugs.
The funny part is where the fear originated from.
Well when I was like 3, I was in my room in my underwear(whiteytighties yay) wondering where my mom was. When I looked down, a roosterroach was crawling on the front side of underwear. So I slapped it off and ran away.
Ever since then, if I see one bug in a room I will not go in that room.
(I am okay with flies and mosquietos...and butterflies...and the moth things. But everything else..aah)