Sandung or sandong is the ossuary of the Dayak people of South and Central Kalimantan, Indonesia. The sandung is an integral part of the Tiwah ceremony of the Ngaju people, which is basically a secondary burial ritual where the bones of the deceased are taken from the cemeteries, purified and finally placed in a sandung.
The sandung is a wooden ossuary shaped like a small house, with ornate roofs, windows, doors, and miniature stairs. Ideally a sandung is made of ironwood, although today lighter wood of any kind of trees can also be used. The house-shaped ossuary will actually be brought by the deceased to the paradise to become their house. Sandungs are painted in bright colors and decorated with carvings representing various religious symbols and patterns. The base of the sandung container is usually decorated with foliage pattern representing the mythical tree of life. Figures of man and woman painted on both side of the miniature door is said to represent a couple which would marry and produce children who will assist their parents in guarding the repository. Other figures painted on the walls of the sandung represents different Ngaju deities from the Kaharingan folk religion. Painting or carving of moon and stars is painted on the downriver side of the sandung, while painting of the sun is depicted on the upriver side; these astronomical landmarks are related with the journey that must be passed by the souls on their way to the Kaharingan paradise, the Lewa Liau. The roof of a sandung is usually decorated with a type of wild chicken. This bird, known as the piak liau, will become a possession for the deceased in the afterlife.
Some sandung are built to contain the bones of a single individual, while others for fifty or more persons. In general, the Dayak people of the Kahayan region prefers large sandung capable of storing remains of many kin, assuring that they will form another household in the afterlife. The Dayak of the Katingan region prefer smaller sandung. A sandung for an individual person (sandung tunggal, "single sandung") is usually build for persons who had died a "bad" or unnatural death, or other reasons which deemed the person remains is inappropriate to be interred with the bones of other family members.