I do believe that's not butter...

One morning when I was in high school I sprayed some "I Can't Believe It's Not Butter" onto my toast. My Dad exaggerated his confused face at me.

"What in the world are you spraying on your bread!?"
I walked over to him, "it's really good, Dad. You should use it. It tastes like butter, but it's good for you."
I handed him the bottle. He tilted his head back so he could read the bottle with his bifocals, "Calories: zero!? Hmmm. Fat: zero!? Jeesh! What the??! This can't be right...sodium: ZERO!? You have got to be kidding me!! Well, ok. I do believe that's not butter...but what the devil IS IT?"