A 17-year-old girl, who previously lived in South America, complained of painful diplopia for 1 month. Two similar transient episodes occurred 6 and 36 months previously. Left abduction and elevation were limited, with 2 mm left proptosis. Orbital MRI revealed a left medial rectus muscle cysticercus (figure). Blood serology was positive for cysticercosis. Rapid improvement followed oral albendazole and prednisone therapy.