The 1999 Astros had to scratch and claw plenty down the stretch during their hunt for the division title that season. This was especially apparent, in a more literal sense, during a chilly late September matchup in Milwaukee that went from uneventful to terrifying in around 15 seconds flat.

A lot was riding on the Astros' game with the Brewers on Friday, Sept. 24, 1999, at old Milwaukee County Stadium. Houston was aiming for its third consecutive National League Central division title (yes, the club was in the NL until 2013) and was unable to shake a relentless Cincinnati team that refused to fade. Entering play on that fateful day, the Astros were up 2 1/2 games on the Reds, but they were also dealing with myriad injuries, and by the time this game in Milwaukee reached the sixth inning with Houston ahead, 2-1, the Astros were nearly faced with one more they weren't expecting -- whiplash.

The victim? Right fielder Bill Spiers. The assailant? Berley "Bert" Visgar, a 23-year-old spectator who used a dose of liquid courage to accept his friends' challenge to jump onto the field and make contact with a player.

"I read somewhere that they dared him to ride a player like a horse," Spiers said in a phone interview with MLB.com. "And I happened to be the horse that he was going to ride in right field."

Spiers, a third baseman by trade, was filling in for an injured Derek Bell that night. Spiers had just finished a round of between-inning tosses with center fielder Carl Everett when he felt someone jump on his shoulders. Initially, Spiers -- who began his career with Milwaukee and played six seasons there -- thought that it might be a Brewers player, perhaps a friend, running from the bullpen to the clubhouse, and using that particular method to say hello.

But then Spiers looked down and saw the person who jumped on him was dressed in blue jeans. And a feeling of dread sunk in.

"I said, 'This is a fan. I have to get him off of me,'" Spiers recalled.

His mind then went to tennis star Monica Seles. This was only six years after Seles was stabbed by a fan while playing in a tournament in Hamburg, Germany. That incident sent chills through every professional athlete in every sport when it happened, and changed the way athletes looked at spectators trespassing on the field.

Visgar turned out to be a formidable wrestling opponent.

"He was big as heck," Spiers said. "I remember thinking, 'Damn. I can't get this guy on the ground.'"

HAMPTON’S MAD DASH

Spiers bent as far forward as he could to try to force him off, and once he got him to the ground, he wrapped his legs around Visgar's legs -- a human trap of sorts.

Enter Mike Hampton. He was the first to reach the area in right field where the incident was happening, which is somewhat remarkable, considering he was on the pitcher's mound when the insanity began.

A few things to know about Hampton: His nickname was The Bulldog. As a high schooler, Notre Dame, Miami and Florida State recruited him to play football. And as one of the more athletically gifted pitchers in the Major Leagues, he could fly.

"I was going to be the first guy out there," Astros Hall of Fame second baseman Craig Biggio said. "And then Hampy ran right by me."

"[Biggio] and Carl Everett, I don't think they knew what to do," Hampton said. "I came in hard. I was there to get him and knock him off."

A circle formed around Visgar, which meant that the crowd was mostly shielded from being able to see what was going on.

Spiers, however, can rattle of his memory of the incident as if it happened much more recently than 20 years ago. He remembers Biggio, a hockey fan, trying to utilize the NHL style of fighting, attempting to pull Visgar’s shirt over his head so he could try to pin his arms up, and Russ Johnson running in and sliding before getting involved.

AN INNOCENT BYSTANDER

The chaos extended beyond the circle formation around Visgar. At that time, on-field staffers were not identified as such. For example, the Brewers grounds crew's attire consisted of jeans shorts and a top with the Brewers insignia and logo. This proved to be problematic, because they looked like anyone off the streets -- or in the stands.

So when one well-intentioned member of the grounds crew ran in to try to help defuse the situation, he instead was cold-cocked by 6-foot-7 Astros reliever Scott Elarton, who apparently took him for a possible Visgar accomplice.

"Elarton grabbed him and just drilled him right in the face," Spiers said. "The guy -- boom! -- goes down. He says, 'I'm the grounds crew.' And we're like, 'Oh my god! We're sorry!' The next day, he's out watering the field with a black eye. We felt awful. But we didn't know."

Eventually, order was restored. Visgar was escorted off the field by police, Spiers replaced a contact lens he lost during the melee and Hampton returned to the mound to finish off the sixth inning. Though he initially stayed in the game, Spiers was replaced by Glen Barker prior to the bottom of the seventh when he was unable to move his neck.

"I had whiplash from when he jumped on my back," Spiers said. "Somebody surprises you, you stand there limp, your neck snaps. I couldn't turn to see the pitcher."

Though the game was close at the time of the incident, Houston rallied for seven runs in the final two innings -- capped off by a three-run blast in the ninth from Everett -- and ended up winning by a score of 9-4.

• Box score: HOU 9, MIL 4

Spiers pinch-hit the next night and finished the season with his health intact. Visgar was arrested and eventually received a 90-day jail sentence.

And the grounds-crew member who was pummeled by Elarton? He received some lovely gifts the next day from Astros players, who plied him with as many signed baseball items as they could muster.

The Astros lost the next two games in Milwaukee but clinched the NL Central on the final day of the season behind a seven-inning, one-run, eight-strikeout performance by -- who else? -- Hampton. Houston would face Atlanta in the NL Division Series and was eliminated in four games; the runner-up Reds fell to the Mets in Game 163 to decide the NL Wild Card winner.

Visgar did not seem deterred by his infamy: For a period of time, his Facebook profile photo featured an image of him being escorted off the field by police that night. According to an online obituary, he passed away early in 2018.

Though 20 years have passed since the incident in Milwaukee, all the players interviewed said people will still ask about it from time to time.

Spiers, who is now an assistant football coach for the Clemson Tigers, has received the brunt of the inquiries over the years.

"It definitely goes up there with the strangest things that I've seen, and definitely gets brought up a good bit," Spiers said. "Then people Google it and I think there's a picture of both of us going to the ground. … Let's put it this way -- it's a good conversation piece."