LOS ANGELES (CBSLA.com) — A boy from Aliso Viejo returned from a family vacation last month with an unusual souvenir when a sea snail egg grew and then hatched inside the 4-year-old’s knee.

Paul Franklin’s parents admit they didn’t think much of it when their son scraped his knee while playing on the beach during a recent camping trip.

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“We cleaned it up, put a Band-Aid on it,” his father, Ken Franklin, told CBS2/KCAL9’s Michele Gile.

“Before you know it, a couple weeks later, his knee was very swollen and infected,” Ken said.

Paul’s parents took him to the doctor, who prescribed antibiotics, and days passed amid fears his wound was badly infected with a dangerous strain of Staph.

“I came home and his knee was the size of an orange and hot to the touch and he’s limping. And I’m like, okay, we have to go to urgent care,” Paul’s mother, Rachael Franklin, said.

The antibiotics helped but throughout August the wound failed to heal.

Then last Thursday, Rachael noticed the spot on her son’s knee was turning black.

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Upon taking a closer look, she decided that she had to drain the wound. That’s when she got a shock.

“It looked like a rock. It was a black thing,” she said.

“I put it on a paper towel and I’m like, ‘That is a weird looking rock. It has swirls on it.’ And I turn it over and it is a sea snail.”

Rachael said when she put the creature in water, she saw it move.

Despite the unnerving ordeal, the family is keeping a good sense of humor about the discovery of the mollusk.

“I just had to laugh because we were going through this three-week ordeal,” the mother said.

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Paul’s parents say they are relieved. They also say Paul’s wound is almost completely healed.