An implant (100) includes a protrusion (110) with an open or rounded loop (112) (or open head) connected to a collapsible anchor. The protrusion may include a straight length of wire (114) or a helical length wire, with one or more wire loops (112) at the end of the length forming the loop. Upon deployment within the gastrointestinal tract, the protrusion expands from a collapsed state, alongside the anchor, to a relaxed state, in which the protrusion extends outward from the anchor. As the protrusion expands to its relaxed state, it pushes the loop into the wall of the duodenum, causing the loop to penetrate the duodenal wall. A pocket of scar tissue forms about the head and possibly through an opening in the head, securing the anchor within the duodenum. The implant may also include a thin-walled sleeve that is coupled to the anchor and extended from the anchor into the intestine.
