The all knowing and all power Sphinx's are a reality. Egypt didn't develop their intelligence on how to build pyramids by themselves. The Sphinx know the mysteries of the universe, but they aren't very good with faces for to id a suspect. Always speaking in riddles, the Sphinx is a very complicated creature let alone hard to understand. Answer the riddle correctly and it will answer one of your questions. Mostly a permanent statue, the Sphinx tend to have low self esteems, so if you pass one by in a museum or library take a second to say hi. Even if they do not answer, they do appreciate the attempt. The sphinx is always keeping an eye on its diet, so don't expect to see these Links drinking normal soda, it has to be diet or low fat before it will consume or drink anything. One thing the sphinx is more afraid of than birds that relieve themselves on statues is grafitti. It is the surefire way to scare them into answering your questions. Quiet the charmer, the Sphinx may be all knowing, but they are most annoying.
Method of killing: You could always scare them to death with a can of spray paint, but typically since these Links are made up of hard stone much like Gargoyles, you should use blue ammo. Typically 2 well placed shots will do the trick.