Oysters are a common term for a number of different species in the Families Ostreidae and Pteriidae, the 'True Oysters' and 'Feathered Oysters', respectively. Generally, True oysters contain the species that are eaten, and Feathered Oysters contain the species used for pearl production. All species, regardless of Family, have two irregularly-shaped hinged shells. Oysters also adhere themselves to a stationary substrate and can form large 'beds' on the sea floor.
|“||Mollusks like clams and oysters use calcium carbonate to construct a skeleton-like casing that is shells.||”|
|— Skulder in School of Dragons|
Oysters eat by filtering water through specialized gills and separating out particles in the water. Their filtration not only provides nutrients to themselves, but can act as a sort of environmental filter for water pollutants.
As yet in the Franchise, oysters are only mentioned for educational purposes.
In reality, oysters are a widely-consumed marine invertebrate all around the world. Some species are seeded with bits of shell so that the oyster will coat the foreign body with 'nacre', creating a pearl.
Oysters are mentioned during the "Wrath of Stormheart" Expansion, when Skulder describes the types of shells in nature.