@jerlands,
When I was at school, the head of RE was a vicar. He took a lot of assemblies. In one of them he talked about other Christian groups he'd met. He stayed with two sisters who were from an obscure denomination but couldn't find anything different about them.
At the end he asked them, and the response was that they live by breathing. He said that everyone does, but they said that's all they do, just breathe, no food or water necessary. He said that he'd seen them eat and drink to which the response was that they weren't very good at it.
That's not a joke.