A 4-year-old California boy's knee injury that was feared to be seriously infected turned out to be something entirely unexpected.

It all started when Paul Franklin hurt his knee while camping during a beach vacation.

His parents kept the wound clean, but it kept swelling, became hot to the touch and painful.

Doctors treated the boy with antibiotics fearing Paul had developed a staph infection.

After three weeks, the spot on Paul's knee turned black.

When his mother decided to drain the wound, a small seasnail hatched out.

Paul is doing fine, but says "It was kind of crazy."