The Liathghorm salmon is prized not only for its flavor, but the unique psychic properties of its flesh.
Before Final Fantasy turned Bahamut into a dragon, it was a fish
A slow, stupid creature that crawls onto people and latches onto them, often on feet, hands, and other extremities, numbing down the area and slowly feeding on it. It's easy to avoid while awake, but nearly impossible to remove once attached. Many an adventurer has been forced to hack off an arm or leg after waking with a Stoneleech wrapped around it. Sleep with one eye open! (This idea came from "Wizard's Rule")