On June 28, 1997, Mike Tyson chewed off a chunk of Evander Holyfield’s ear. Twenty years later, boxing is still bleeding from the wound.

The spectacle of one boxer biting off a body part of another in the name of sport was unheard-of even in the often brutal world of the prize ring.

Boxing has had its share of great fighters doing inexplicable, self-destructive things in the heat of battle. Jack Dempsey stood over Gene Tunney in their 1927 rematch, possibly costing himself a chance to regain the title in the famous Battle of the Long Count. Roberto Duran impulsively quit on Sugar Ray Leonard in the eighth round of their 1980 rematch, introducing the words “No mas’’ into the sports lexicon.

But never has a fighter done what Mike Tyson did that night.

All professional sports have had their moments of infamously unsportsmanlike behavior—Juan Marichal hitting John Roseboro over the head with a baseball bat in 1965, Kermit Washington levelling Rudy Tomjanovich with a sucker punch in 1977, Pete Rose steamrolling Ray Fosse in the 1970 All-Star Game (for Christ’s sake!). But the deliberate biting of an opponent’s ear, and not just biting it, but tearing through the flesh and cartilage and ripping it away from the skull, the way a rabid animal would flay the meat off a carcass, was unimaginable even in the world of professional prizefighting.

At the time, it was taken for granted that the career of Mike Tyson, which had begun in such promise 15 years earlier, had now ended in disgrace. And for many, it appeared the same fate would befall boxing.

“It was horrific,’’ says promoter Bob Arum.

“Human beings don’t do things like that,’’ says former HBO vice-president Ross Greenburg.

“I wondered if we were watching the end of boxing as we know it,’’ says Mike Weisman, the producer of NBC Sports fight telecasts for nearly 20 years.

“I still can’t believe I bit his ear. What was I thinking?’’ Tyson wrote in the forward to “The Bite Fight,’’ George Willis’ 2013 book about that unforgettable night.

And in fact, that fight—considering the shock of their first meeting, the viciousness of the pre-fight buildup, and the amount of worldwide attention focused on this event and those two athletes—might very well have dealt a KO blow to a sport that has seemingly been dying a slow death for the past 40 years.

If not, of course, for the grace and courage of Holyfield: “I think what I did that night saved the game of boxing.”

The fight lasted eight minutes and 21 seconds, but its repercussions are still felt two decades later. And as he often is, Holyfield was absolutely right.