On Wednesday, doctors in France reported a rare case of tiny sheep bot fly larvae—aka maggots—infesting the outer surface of a man’s eyeball.

The small, spiky larvae were seen slithering around the man’s peeper, explaining the redness and itchiness he was experiencing. Doctors counted more than a dozen of the disturbing grub-like critters outside the eyeball and surrounding tissue. To clear out the bloodsuckers, doctors had no choice but to pluck them out, one by one, using forceps. The doctors also prescribed topical antibiotic treatments in case they missed any bugs.

Sheep bot flies, or Oestrus ovis, are found worldwide in areas with sheep. They typically deliver their squirmy offspring to the nostrils of sheep and goats. The larvae mature in their nasal nurseries, then fall to the ground and pupate in the environment before transforming into parasitic pests. But, on rare occasions, adult female flies become bleary-eyed and lay festering broods in a human eyeball, causing a disease called ophthalmomyiasis. This is typically a dead end for the flies; the larvae generally don’t make it to adulthood in the human eye. But if you think the unfortunate infestation is nothing to wince at, you’d be incorrect.