12. Mantis Shrimp
Although you may not think a shrimp can be terrifying, the mantis shrimp just might change your mind. These highly aggressive shrimp are categorized by two types; one that kills its pray by clubbing it to death with its specially adapted appendage, and the other that stabs it with its razor sharp spear. They strike so fast when they’re hunting that even if they miss, the shock wave they produce can kill the prey. They spend most of their lives solitary, looking for their next victim.