Caeleb Dressel lit up the pool by winning his fourth, fifth and sixth gold medals on Saturday but even his electric performance failed to brighten the mood on a dark day at the world swimming championships in Gwangju.
Athletes awoke to news that several water polo players had been injured in a terrifying accident in the early hours of Saturday morning when the second floor of a nightclub came down on the heads of revellers below.
The athletes, who had been letting off steam at the end of their tournament, escaped serious injury but two South Koreans were killed.
There was more bad news later in the day when Australian freestyle swimmer Shayna Jack, who had withdrawn from the worlds just before the meet began, said she had tested positive for a banned substance.
The positive test comes as a major embarrassment to Australian swimming given the headline-grabbing podium protest that 400 freestyle silver medallist Mack Horton made on Sunday over Sun Yang's participation at the worlds.
The Chinese swimmer, who served a doping sanction in 2014 and was labelled a "drug cheat" by Horton at the Rio Olympics, is competing under the shadow of a World Anti-Doping Agency appeal against FINA's decision to clear him of wrongdoing during a random drug test last September.
Sun said he did not deserve "insult and slander" from rival swimmers and that he did not violate any rules during a controversial doping test last year.
Australian freestyler Cate Campbell said Jack's absence was proof of her team's anti-doping commitment.
"I think that once more information comes to light we can pass judgement but at the moment the Australia team stands for clean sport and unfortunately that is why Shayna is not with us," she said.
While Australia were left reeling by the positive test, the US team focused their energies on the pursuit of gold.
Sprint sensation Dressel, who had already won three gold medals in Gwangju, added the 50 freestyle and 100 butterfly titles to his collection before helping the Americans to victory in the mixed 4x100 freestyle relay.
The 22-year-old has been the big story of the championships, grabbing golds and breaking world records in the manner of Olympic great Michael Phelps.
Dressel now has 13 world titles from two world championships. Phelps won 26 golds from six appearances at the worlds.
Freestyle queen Katie Ledecky finally got to the top of the podium in South Korea, holding off a brave challenge from Italian Simona Quadarella in the 800.
Ledecky had surrendered her 400 title to Australian Ariarne Titmus earlier in the week before pulling out of the 200 heats and 1,500 final due to medical reasons.
Unfortunately for Quadarella, who won the 1,500 in Ledecky's absence, the closing speed that had deserted the American in the 400 had returned.
"I took it out like I usually do and just kind of relied on my training to bring me home," she said.
"Simona was having a great race and pulled up right next to me and when she did that I kind of felt like I could stick with her and rely on my speed."
A night after setting a world record in the semi-finals of the women's 200 backstroke, 17-year-old American Regan Smith returned to win the final, while the mixed 4x100 freestyle saw the U.S. team win their fifth gold of the night.
The only world title to escape the Americans' clutches on Saturday was the women's 50 butterfly, which went to Sarah Sjostrom - the Swede's first gold of the meet.
"I’m very happy that I could win another gold medal especially after such a tough programme I’ve been having," said the Olympic 100 butterfly champion, who had needed an oxygen mask after winning bronze in the 200 freestyle.
"I don’t think I ever had such a tough programme in a big championships like this before."
The meet concludes on Sunday.