Disclosed are embodiments of a device for occluding a left atrial appendage (LAA) and other cavities or openings within a body. Some embodiments of the device can include an implant configured to be deployed within the LAA or other cavity, configured to be expanded or moved against a wall portion of the LAA or other cavity, and configured to twist at least a portion of the LAA or other cavity when the implant is rotated. Thereafter, one or more securing elements, staples, sutures, or other fasteners can be implanted in the gathered tissue to hold the tissue in the gathered state, thereby occluding the opening of the LAA or other cavity. In some embodiments, the opening of the LAA or other cavity can be occluded by elongating or otherwise reshaping the opening using an implant device, and securing the opening in the occluded state.