Trivia Answer:
Jim 'Mattress Mac' McIngvale of Gallery Furniture in Houston
Back in 1975, Mac was running a chain of health clubs in Dallas. Ali was fighting an exhibition and pulled Mac (the only white guy there) out of the crowd to spar with. As they circled the ring Ali whispered that he would let Mac knock him down in the second round and that Mac should then scream a racial epithet at the audience.
Ali was a good actor and Mac played his part just as well. Mac's early demise was averted when the Champ jumped up and revealed his prank.