 Hello everyone! We are back with the case of the month. I hope you and your family are safe and healthy. We, as Indian radiologists, would like to thank Agnito for their association with us. A 39-year-old female patient presented with history of abdominal pain, distention and vomiting. An MRCP was asked for. T2 non-fax act coronal image shows mildly distended gallbladder with thickened walls, dilated stomach and dodenum. Exiled T2 non-fax act and fat act images show presence of intraluminal T2 hypointensity in non-dependent part of fundus of gallbladder with pericolastic edema and fat stranding, which is better demonstrated on fat act images. These images show presence of a large colloidal fistula. Intraluminal T2 hypointensities are seen in non-dependent parts of CBD and proximal biliri radicals. These hypointensities in non-dependent parts of gallbladder, CBD and proximal biliri radicals represent air and are suggestive of pneumobilia. Stomach and small bowel loops are dilated with a large, well-defined T2 hypointensity within the terminal ilium, representing a large, passed-out gallbladder calculus. Hepatomegaly and acitis are also seen. Overall findings of pneumobilia, colloidal fistula and a large T2 hypointensity within the terminal ilium, which represents a passed-out gallbladder calculus, are suggestive of gallstone alias. Gallstone alias is an uncommon cause of mechanical small bowel obstruction and is a rare complication of chronic colostitis. It occurs when gallstone passes through fistula between the gallbladder and small bowel before becoming impacted at the iliocecal valve. It is commonly seen in elderly females who present with abdominal pain and distention in the course of small bowel obstruction. Repeated bouts of colostitis result in addition of the gallbladder to the small bowel, which is usually duodenum, with eventual fistula formation and passage of gallstones into the lumen. Small stones presumably pass without incidence. However, large stones can become impacted, typically at the iliocecal valve. Radiological findings consist of regular striad, which is small bowel obstruction, pneumobilia and a gallstone, usually in the striad at the iliocecal valve. When the stone is impacted in duodenum or stomach, it leads to gastric outlet obstruction, known as Bouverte syndrome. Thank you for watching.