Frogo "Stubs" Gurble was a deceitful grue
and author of the book
"Grues: Another Look," published sometime prior to 1066 GUE
for a human audience, he purposely misled adventurers by advising in
it, that the best thing to do when grues were approaching was to
become still and silent.
|SOURCE(S): Zork: The Undiscovered Underground|