A gastrointestinal implant device includes a flexible, floppy sleeve, open at both ends, that extends into the duodenum. The device further includes a collapsible anchor coupled to the proximal portion of the sleeve. The device further includes a drawstring that is threaded through a proximal end of the anchor, and barbs that extend from the exterior surface of the anchor. The collapsible anchor can be a wave anchor. The drawstring can be used to collapse at least a proximal portion of the implant device. This is useful in removing or repositioning the implant device.