"He fell down, scratched his knee. We put antibacterial spray and a band aid, and out we went," Brian Baumkirschner, the 3-year-old's father recalled.
Brian says little Beauden spent the next few hours riding bikes, running around and at one point, playing in the dirt.
"Just before 6 p.m. he said, 'My tummy hurts. Is it bedtime?'" Brian told KGTV.
The next morning, Beauden woke up with a fever and eventually started favoring his right leg, where he had scraped his knee area.
When he became lethargic the next day, his parents rushed him to urgent care, and then Rady Children's Hospital.
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Brian says his son's right knee was swelling up and turned purple.
"It started spreading up his legs, arms, down to this hands," Brian recalled.
Brian says doctors eventually diagnosed Beauden with a MRSA staph infection.
"They kept telling us, 'There's swelling. All of his extremities are shutting down,'" Brian said.
Beauden had developed a complication, toxic shock syndrome. His little body started to shut down.
He then developed sepsis, and his kidneys started to fail.
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"Every parent's worst nightmare," Brian said. "You can't do anything. You're helpless."
Several leg surgeries to relieve the pressure helped save Beauden's life.
But on Monday, doctors had to amputate his legs below the knee.
Brian is optimistic Beauden's arms and hands can be saved. He says he's just grateful is son is alive after their fun vacation turned tragic.
"We're still so numb, just heartbreaking," Brian said.
The family has set up a GoFundMe to cover some of Beauden's medical expenses.