California doctors removed a live tapeworm from a man’s brain, after determining the patient’s intense headaches were caused by the parasite.

Luis Ortiz spent nearly three months in a Napa Valley hospital, after suffering debilitating pain that spurred fits of vomiting. His doctors ended up finding a live tapeworm trapped in the depths of his brain and removed it, the Los Angeles Times reports.

“It was still wiggling and moving around,” the 26-year-old Napa native said.

Doctors believe the worm moved its way from another part of his body and settled into a ventricle in the middle of his brain, said Janet Bruneau, an acute care nurse practitioner at Queen of the Valley Medical Center.

Doctors don’t know how the worm entered his body. Swimming in lake, eating uncooked pork, or dirty fruits and vegetables could do it. But Ortiz can’t remember doing any of those things.

Tapeworm infection is mostly found in developing countries, where poor hygiene is more prevalent, according to the Centers for Disease Control and Prevention. It can result in death in cases where the tapeworm forms cysts that spread to the brain and spinal cord.