Art Jimmerson was the boxers name. That fight was in UFC 1 way back in 1993. I believe that was the 3rd fight of the night and the first time we got to see Royce Gracie. He was originally going to wear both boxing gloves, then decided to take the one off.
He was actually a pretty good boxer at one time, 29-5 pro record, former Golden Gloves Champion. He was definitely on the downslide of his boxing career though, he retired with a record of 33-18, 13 of his losses occuring after his MMA match with Gracie in 1993 thru his retirement in 2001 and almost all of those being KO's or TKO losses.