Sir Alex Ferguson's recently released book has a particularly scathing section on his former captain at Manchester United, Roy Keane.
Ferguson describes the moment he realised it was time to end Keane's career at Old Trafford and move him on, claiming an unreleasable interview for MUTV where the Irishman laid into a number of his teammates as the catalyst.
Very few Manchester United players were spared the former Nottingham Forest man's sharp-tongued treatment and Ferguson felt he had gone too far, offloading him to Celtic at the earliest possibility.
GMS always found Keane to be quite scary and believe his hard stare as possibly one of the most chilling expressions in Premier League history.
So, we got thinking about some other scary or eccentric stars to have graced the game on England's shores and picked out five of them.
Click on to the next page to see the choices...
If you think we have left out someone who is more unhinged than the following names, make sure to enter the discussion below.