Terrina are creatures with a hard shell, akin to rock. They're a kind of centipede with magical potential. Their shells, antennas, and themselves can be used for potions. Their shells are commonly used for a strong defense potion, but since they're only found in dark places and Ackrex, it's hard to catch them. They also have a strong bite, that although isn't actually fatal, hurts an awful lot. They luckily will leave you alone if you leave them alone.