When I was a child, I went through a Digimon phase. One night me my brother were outside jumping on a trampoline or something and we saw some little floating lights swirling around us. There seemed to be more and more of them and I got terrified cause I thought I was getting sent to the Digimon realm or something, so he and I ran away screaming. So that was my first experience with fireflies.
mice can also rear up, jump pretty high, and scream like a motherfucker.
one mouse managed to startle me and actually scared my cat. but then, a tiny aggressive songbird also managed to intimidate my cat.