An 81-year-old woman residing in a nursing facility due to dementia presented with a 5-day history of vomiting and anorexia. Computed tomography revealed air-containing material in the esophagus, and sponge fragments had been noted in her vomitus 4 days earlier. Accidental sponge ingestion with esophageal impaction was suspected, and emergency endoscopy was performed. The sponge was friable and fragmented easily, making removal difficult. Standard tools including grasping forceps, snares, and nets were ineffective, but a five-pronged grasping forceps enabled successful removal. Follow-up endoscopy revealed an esophageal ulcer presumedly caused by pressure from the sponge, without bleeding or perforation. The ulcer recovered with proton pump inhibitor therapy. Sponge ingestion is a rare cause of esophageal foreign bodies but may become more frequent due to the growing elderly population with cognitive impairment. Sponge is potentially dangerous as it may cause mucosal injury or perforation. However, because they allow fluid passage, symptoms may be mild and diagnosis delayed. Once beyond the duodenum, endoscopic removal becomes extremely difficult. Therefore, sponge foreign bodies should be removed endoscopically when feasible, and simply displacing them to resolve obstruction is not sufficient.