Device for treating obesity and gastroesophageal reflux disease (GERD) by intussusception of part of stomach tissue

A device (200, 1100) to create an intussusception in a part of stomach tissue by introducing telescopically, of a portion of stomach tissue elsewhere stomach tissue, wherein the device comprises: a shaft (307, 64, 702); a component (309, 602, 1110) creating radially expandable intussusception coupled to the shaft and arranged to create the intussusception; at least one anchor (802, 1120) for use during the intussusception; at least one introducer anchors (305, 706, 1118) arranged to expand away from the axis and arranged to expand away from the axis and arranged to use at least one anchor during intussusception.