Conor McGregor, the brash Irish mixed-martial arts fighter whose fame and showmanship transcended the sport he helped spread worldwide, said he was retiring in a message on Twitter today. After McGregor announced his retirement on social media, it was reported that the famous fighter was under investigation in Ireland after a woman accused him of sexual assaulting in a Dublin hotel last December. I wish all my old colleagues well going forward in competition. I now join my former partners on this venture, already in retirement. Proper Pina Coladas on me fellas! I have decided to retire young. Thanks for the cheese.