Pancreatic pseudocysts are a common complication of pancreatitis. Conservative management and repeat imaging are appropriate to monitor spontaneous regression. However, in some cases, rupture and haemorrhage of pseudocysts can lead to life-threatening events requiring urgent intervention. We present a male patient in his 30s who was presented to the emergency department with severe pancreatitis in the context of alcohol excess. Past medical history included pancreatitis with a small pseudocyst and splenic vein thrombosis for which he was anticoagulated six weeks previously. Computer tomography of the abdomen and pelvis showed an interval increase in his pseudocyst with haemorrhage secondary to a suspected splenic artery pseudoaneurysm. He was admitted for attempted embolisation and observation. Serial imaging demonstrated progression of the pancreatic pseudocyst and then spontaneous interval decompression via a transgastric fistula, leading to a natural cystogastrostomy confirmed on subsequent endoscopy. We discuss the uncommon sequelae of a complication of pancreatitis, and consider the hypotheses related to this rare occurrence, with suggestions for management and follow-up of these patients.