Everyone thinks it's those pesky sharks you need to watch out for when you're reeling in fish around a reef. What people don't realize is that more often than not, it's a big, mean grouper that chomps your catch, not a hammerhead. Goliath grouper in particular have no qualms about shooting up from the bottom to grab an easy meal. In the video below, a catch this spearfisherman thought was secure was actually far from it. He might have to change that wetsuit after this one.