Manicina areolata is a free-living coral that lives loose on the sea floor, and is one of the few corals that can be actively mobile.
If a colony becomes overturned by a fish or current then it is able to right itself and avoid smothering in the sediment. This behavior only occurs at night when the coral polyps extend for active feeding. To overturn, the colony fills its stomach with sea water so it becomes bloated, and then alternatively jets water from one side and then another of the colony. This causes the colony to rock back and forth until the center of gravity is surpassed and the colony rapidly flips upright. The entire process takes a few hours until the final flip occurs in an instant.
Large colonies are less able to re-orient themselves because of the weight of the skeleton increases with the volume of the colony and the power of the water jets is related to the surface area. Thus, once overturned, large colonies are more likely to die by smothering in the sediments. This places an upper limit on the size of the colonies and explains why in most habitats colonies rarely grow more than 10 cm in size.