A 32-year-old man presented to the author's hospital with a 1-day history of acute onset epigastric pain after the ingestion of Japanese sushi (bite-sized pieces of cold cooked rice topped with fish, eggs, or vegetables and wrapped in seaweed). The patient had no medical history, and the patient's vital signs were normal. Emergency endoscopy revealed a whitish linear worm penetrating into the mucosa in the gastric corpus (Fig. 1, Panel A). What is the diagnosis?