Full-back Mike Brown was given the nickname by his Harlequins team-mates on account of a fiery temperament that has been transferred from club to international stage.
Two weeks ago Brown squared up to Brian O'Driscoll in the 13-10 RBS 6 Nations victory over Ireland after a heated exchange of words that he confesses is an intrinsic part of his playing psyche.
"I was called 'Mr Angry' when I first joined Quins but it's not about being angry. I'm competitive and want to win," he said.
"I'm always fired up. Every time I step on the pitch I'm fired up to play. I want to do the best I can for whatever team I'm playing for.
"I enjoy the confrontational side of rugby, standing up for myself or a team-mate. That competitiveness applies to most sports.
"Being on a rugby field is probably where I feel most comfortable on life.
"As soon as I step out there I feel confident and feel like I grow as a person. I love being out there."
Brown's spirit is matched by his ability on the pitch with successive man of the match performances placing him on course to be named player of the Championship.
Another stellar performance in Sunday's clash with Wales, in which he will line-up opposite British and Irish Lion Leigh Halfpenny, will continue to his ascent to world class.
He is now mentioned in the same breath as Israel Dagg and Israel Folau, yet the 28-year-old is reluctant to be viewed as anything other than a cog in the wheel.
"I don't really see myself as the star of the team, it makes me feel a bit uncomfortable," he said.
"I feel pressure in very game to play the best I can. I've shown in a Quins shirt that I want to play well in every game. When I'm not I'm pretty hard on myself.
"Sometimes I look at the negatives before I look at the positives, so I don't feel pressure outside of myself.
"I guess that focus on the negatives has helped drive me to become the player I am. It's fine as long as I don't dwell on them too much.
"I don't think I have recently because I've matured a person and as a player."
The growing ranks of Brown's admirers now include former Manchester United goalkeeper Peter Schmeichel, who has promised to start following his career.
Brown revealed that his spectacular diving save against Ireland, in which he plucked a kick from O'Driscoll out of the air, was inspired by Schmeichel and the Dane subsequently sent a video message in support.
"I was overwhelmed to get a message like that from someone who has played at the highest level in one of the best teams in all sports in that treble winning team," Manchester United fan Brown said.
"I'd like to meet him, but then I'd like to meet all the Man Utd players past and present, that would be great. It would be good to meet him in person and thank him."
- Sports & Recreation