Among the Merina and Betsileo of the highlands, a family will periodically open the ancestral tomb, bring out the remains of its dead, rewrap them in fresh silk lambamena, carry them about, speak to them, dance with them and then return them. This is famadihana, the turning of the bones. It is held every several years rather than annually, in the dry season, and it is expensive: the shrouds, the musicians, the cattle and the feeding of everyone who comes can absorb a very large share of a family's resources.
The logic is not commemoration. In the Malagasy understanding the recently dead are not yet fully ancestors; the transition takes time and requires the attention of the living, and the wrapping is a form of care given to someone who is cold. The occasion is also the moment at which the extended family assembles, quarrels are settled, and the tomb, which is often the most substantial structure a family owns, is repaired. It is a cheerful event.
The churches have had to decide what to do about it. The Catholic Church came to treat famadihana as a cultural practice compatible with Christian faith, provided the prayers said are Christian, and Catholic families hold them. Many Protestant churches accommodated it similarly. Some evangelical and Pentecostal churches condemn it outright as ancestor worship, and refusing to participate has become one of the visible markers of conversion to those churches, with real cost inside a family.
Two pressures have reduced the practice: the expense, and public health guidance during plague outbreaks, since Madagascar has endemic plague and handling remains has been identified as a transmission risk.