Anung Un Rama (Hellboy's actual name) also known as the Beast of the Apocalypse. Every once in a while Hellboy's horns grow out and the Crown of the Apocalypse appears over his head. This was a greatly simplified explanation ;) ... but this character could be described as the "evil" Hellboy. The one the forces who summoned him to earth want him to be.
The official Hellboy website is at www.hellboy.com