Cretin is the term for the adventurer in the Zork universe. Upon asking, "what is cretin?" the games answer, "That is difficult unless your eyes are prehensile." (which is the games' answer to the command "look at self".) Another time the adventurer is addressed as "cretin" is in Zork I, upon burning the black book. A booming voice says "Wrong, cretin!" and you notice that you have been turned into a pile of dust. How, I can't imagine.
Other refences to self-image in Zork I appear with the use of mirrors. Only in the presence of a mirror will "what is cretin" yield a different answer: "Your image in the mirror looks tired." If a user types "look at mirror" the game responds with a quip: "There is an ugly person staring back at you."