THE ENFORCERS
The five recent rugby enforcers you’d least like to bump into in a dark alley.

JERRY COLLINS
A self-described “mercenary”, Collins is easily the most feared man in world rugby.
Not because he chews ears or rucks craniums. Collins isn’t what you’d call a dirty player.
It’s because people genuinely fear coming into contact with the strapping Samoan-born Wellingtonian, and justifiably so. Colin Charvis, Steve Devine and Chris Jack are just a few of the unlucky souls who have been unfortunate enough to have been on the wrong end of a thumping Collins’ hit.

OLIVIER MERLE
Merle was introduced to add mongrel to a struggling French pack in the early 1990s.
The hulking 130kg lock, known as ‘Le Massif Central’, was sued by Ricky Evans in 1995 after his deliberate head-butt caused the Welsh prop to fall awkwardly in a ruck where he suffered a double fracture to his left leg. A French disciplinary committee later cleared the unblinking hardman – once described by former England manager Geoff Cooke as a “joke” – of foul play.
Follow up:

WAYNE "BUCK" SHELFORD
The very epitome of hardness, Shelford suffered a ripped scrotum (and lost four teeth) in only his second test for the All Blacks – against France in Nantes in 1986. To the horror of the physio, Neil Familton, Shelford instructed him to start sewing and he returned to the field. The former All Black captain gets extra points for his fearsome haka performances and knocking out Welshman Huw Richards with a short right in 1987.

WILLIE OFAHENGAUE
The ‘Tongan Torpedo’ was the ball-running and crash-tackling revelation of the 1991 World Cup. Ofahengaue was an All Black in the making, representing the New Zealand Schoolboys in Australia in 1988, but he was refused re-entry to the land of the long white cloud on his Tongan passport, so New Zealand’s loss became Australia’s gain.
Ofahengaue went on to earn 41 test caps for the Wallabies from 1990-98, gaining the rare distinction of having beaten the All Blacks more times than losing to them.

DEAN RYAN
Ryan built a reputation as one of the most fearsome performers in the English game during his time with Saracens, Wasps, Newcastle and Bristol. The former England No 8 guided the Falcons to a Premiership title at their first attempt in 1997/98. Brave to a fault, Ryan was knocked out three times in a week in the run-in to the championship success, including one occasion when he was unconscious for eight minutes.
Source: New Zealand Rugby News
To this list I would add a couple of other noteworthy 'Nutters':
1. Richard Loe (New Zealand)
2. Lewis Moody (England)
3. James Small (South Africa)
4. Paul Ringer (Wales)
5. Os Du Randt (South Africa)