Greatshell
A Greatshell is type a large, crustacean-like animal native to Roshar. They, including the smaller species, are called shellbeasts. They include Chasmfiends, and their lesser cousins, Chulls, Marabethian marine greatshell, and others, including extinct lanceryn. Larger species have a large gem inside of them, called a Gemheart. Greatshells are usually wild and hunted for their gemhearts, edible meat and carapace, although some species are domesticated.
Their blood is violet, and has a musty, moldy smell.
They have no tongue, and a complex set of jaws. Chasmfiends, for example, have some flat platelike teeth for crushing and destroying shells and other, smaller mandibles for ripping off flesh or shoving it deeper into the throat.
Dead greatshells attract a strange kind of spren, that is never seen anywhere else.
People from Kadrix are rumored to ride greatshell beasts.