There are a lot of shark deterrents out there. It makes sense, too–spending the last minute-or-so of your life simultaneously being torn apart and drowning isn’t exactly… appealing. Much better to die peacefully in one’s sleep like Grandpa did, not screaming like everyone else in his car.
Shark Eyes, though, might be my favorite. Not because it works (and it might!), but because it’s so damn simple and doesn’t pretend to be anything else. It’s just a sticker of some giant eyeballs. Remember that Calvin and Hobbes strip where Calvin puts a mask on the back of his head so Hobbes can’t sneak up on him? “I’ve finally thwarted your murderous recreation!” he says. It’s like that, except hopefully without the Hobbes reaction.