What ancient device allows people to traverse through walls?

My first four letters describe all living things. My last five letters are another word for knight. My job is to save you, and I’m a fan of water. Who am I?

How do trees surf the internet?

What is a surgeons' favorite game?

What did the panda ghost say?

I am the opposite of eat, I am savory and sweet. I am a treat, yet still a drink. What am I?

I am as light as a feather, yet the strongest of men cannot hold me for more than a minute. I am with you from the day you are born to the day you die. I can be as putrid as onions and garlic, yet as pleasant as freshly picked roses. What am I?

How can you tell if reindeer have passed on your roof?

I take months to build, seconds to destroy, and years to rebuild. What am I?

What do you call dental X-rays?