4. Cone Snails
Source: Iconosquare
Living inside brightly colored conical shells, this animal has been known to kill humans who attempt to add it to their seashell collections. Cone snails have causes over 20 deaths since 2011. It injects venom using a harpoon which fires, like a bullet, powerfully enough to penetrate bone. Its venom is made of over 200 toxic compounds and is strong enough to kill 15 people. This militant little beast carries up to 20 poison projectile barbs at a time.