This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Leontophone (Medieval Bestiary)
Leontophone (Leontophonos, Leophontes) is a small animal from Medieval bestiaries that is deadly to lions. To be killed, the lion need only bite the leontophone. Though, in a proper ritual, the leontophone's flesh is burned and its ashes are sprinkled on a piece of meat, which is placed at a crossroad; if a lion eats even a small amount of the tainted meat, it dies.
The ancients considered this method a 'happy arrangement', since both lions and leontophones die in the process; from this, one can safely assume that not only were lions considered dangerous, but leontophones may have been considered pests. Likewise, due to the danger they pose to lions, lions instinctively hate leontophones. Confronted by a leontophone, they often hunt and kill them, tearing them apart with their claws rather than biting them.