Pancreatic pseudocyst is a common complication of pancreatitis. Pseudocysts may require decompression when they become painful, infected, or start compressing surrounding organs. Decompression is achieved by endoscopic cystogastrostomy. Recently, the use of lumen-apposing metal stent (LAMS) for cystogastrostomy has gained popularity due to ease of use and high technical success. LAMS has a wider lumen, which allows for direct endoscopic necrosectomy in the cases of walled-off necrosis. Our patient is a 30-year-old male who presented with massive hematemesis and dizziness. He had a history of chronic alcohol-induced pancreatitis. Three weeks before the presentation, he underwent a cystogastrostomy with LAMS placement to treat a 10-cm walled-off necrosis. Urgent computed tomography (CT) scan did not reveal any acute finding suggestive of bleeding. Esophagogastroduodenoscopy showed blood protruding from the LAMS with a large clot formation. Attempts to stop bleeding were unsuccessful. He underwent CT angiography of the abdomen. CT angiography showed a bleeding pseudoaneurysm (PA) believed to be a complication of the LAMS. Subsequently, multiple coils were placed in the splenic artery near the PA. The patient continued to improve without a further drop in hemoglobin and was eventually discharged. PA formation and subsequent rupture is a rare delayed complication of LAMS. It may lead to massive gastrointestinal bleeding with a high mortality rate. Diagnostic delays have resulted in increased mortality by 60%. In this article, we present a case of massive gastrointestinal bleeding due to a ruptured splenic artery PA presenting as a delayed complication of LAMS.