(Urban Dictionary: Top Definition: cray cray: meaning really crazy)
The Kray brothers were British gangsters who menaced London’s East End and Soho nightlife in the Swinging ‘60s. One brother was bad; he was very, very bad. The other brother—he was worse. Tom Hardy plays both.

(L–R) Ronnie and Reggie Kray (Tom Hardy) in "Legend." From Academy Award winner Brian Helgeland ("L.A. Confidential," "Mystic River," and "Working Title") comes the true story of the rise and fall of London's most notorious gangsters, both portrayed by Hardy in a powerhouse double performance. Universal Pictures/Universal Studios