When Ken Franklin picked up his 4-year-old son from daycare and asked how his day went, he got a pretty nonchalant answer.

"He said, 'Oh, dad, I pulled a snail out of my knee,'" Franklin told ABCNews.com with a laugh. "I said, 'That's nice. Here, have some popcorn.'

It wasn't until Franklin got to his Orange County, Calif., home and talked to his wife that Franklin realized their son, Paul, wasn't making it up. The little boy had cut his knee three weeks earlier and must have gotten a snail egg in the wound. A snail popped out before his mother dropped him off at daycare.

Read about another cool 4-year-old - who happens to be mayor of a small, Minnesota town.

The family went on a camping trip the weekend of July 20 and decided to take a walk along the beach. Fascinated with a bug in his pail, Paul didn't notice a chair-sized rock in his path until it was too late, Franklin said.

Paul "did a face-plant" and scraped his knee. Used to his accident-prone son's frequent cuts and bruises, Franklin cleaned him up, applied some antibiotic ointment, and slapped on a Band-Aid.

But the wound stayed swollen for three weeks.

On Aug. 8, Paul's mom noticed a "big puss ball" on Paul's knee, Franklin said. So she gave it a squeeze, and the wound looked oddly black, Franklin said.

"Rachael squeezed it, and sure enough, a snail popped out," he said. "It was really freaky."

They named the snail Turbo after the hero of this summer's animated DreamWorks movie of the same name. The snail only lived for about a day after emerging from Paul's knee, but he still has the shell.