Several embodiments are set forth of devices, systems and methods for modifying an atrial appendage such as a left atrial appendage (LAA). In one embodiment, a device includes a body that is collapsible and self-expanding. The body includes a textured surface with protruding portions and recessed portions. The body may be formed of a reticulated foam material and may exhibit a substantially spherical geometry or a truncated spherical geometry. The body may be substantially hollow. In one embodiment, portions of the textured surface may be metalized or have a coating placed thereon to enhance frictional engagement of the body with the atrial appendage wall. In another embodiment, a mesh bag is disposed within an LAA and one or more self-expanding bodies are disposed within the mesh bag. The mesh bag is then secured to retain the self-expanding bodies within the bag and the LAA.