Sharks... Like I am scared shitless of going swimming in the middle of the ocean or a sea and just being attacked by a shark. I was with some cousins in the Red Sea this summer on a yacht and they were all jumping in cannonballing and I wouldn't go in, so one of them pushed me off in the middle of the sea. As soon as I was under water and opened my eyes and saw the darkness of the sea, I was scared shitless that a shark would just pop up out of nowhere. Probably pretty irrational, not even sure that sea had sharks but god damn they're scary. I'm not scared of them in aquariums and stuff, but swimming in the ocean with them is a huge fear.