Colonic lipomas are benign mesenchymal tumors arising from the bowel wall (submucosal). Most occur in the right colon and are asymptomatic. They uncommonly cause intussusception/obstruction, as in this case.
This lipoma is likely pedunculated, and acted as a lead point for forming the intussusception, with peristalsis propelling it from the upper ascending colon/hepatic flexure into the mid transverse colon. The small foci of air surrounding the lipoma are likely due to ulceration of the overlying mucosa.