Have you never heard of The Killer Beast of Caerbannog?
Follow! But! follow only if ye be men of valor, for the entrance to this cave is guarded by a creature so foul, so cruel that no man yet has fought with it and lived! Bones of four fifty men lie strewn about its lair. So, brave knights, if you do doubt your courage or your strength, come no further, for death awaits you all with nasty big pointy teeth.