The infamous 'Ghost Pepper' is a devil-like chili: a slightly sweet, super-hot pepper that burns for a long time.
The Chocolate variant (also known as Ghost Pepper Chocolate or Naga Jolokia Chocolate) has a dark brown skin color. It has a more subtle flavor - slightly sweeter with a hint of smoky - reminiscent of other "chocolate" chili varieties such as the Habanero Chocolate and the chocolate scorpion peppers.
It is delicious in extreme barbecue sauces, hot sauces and marinades.
Warning: Using this pepper requires extreme caution. Wear hand, eye and breathing protection.