Baylisascaris procyonis, a parasitic infection of raccoons, causes severe neurologic and ocular disease in humans when infectious eggs from raccoon feces are ingested. In the absence of a serologic test, definitive diagnosis is challenging but can be made by isolation of larvae in brain biopsy, direct visualization of the worm in the eye, or exclusion of other potential causes of eosinophilic meningoencephalitis. Currently, no effective treatment has been identified, making preventive efforts critical.