It causes small thrills to skinny up and down the neck. It burns the nose and waters the eyes. It is written that this should be so. I have read several hundred pages of what's been written by experts about hot peppers and I know a thing or two. I know, for instance, that what makes a chili pepper hot is a substance known as capsaicin.
Mild peppers have a small amount of capsaicin and extra hot ones have a lot of it.
My personal theory is that once in a long while nature plays a joke on pepper consumers, in the form of a genetic accident that pumps a great dose of capsaicin into a single pepper and makes a bomb of it. I have a small jar of hot sauce some friends brought me from Brazil. It was made with native peppers down there. I won't try to tell you how hot it is, except to say they gave me four ounces three years ago and two ounces are still in the bottle. I wonder if the man in search of concentrated pepper heat would be interested in that sauce.