cyclops, Dungeon of Zork, 948 GUE (A)(B) / (C)
    cyclops with earplugs (Great Monster Uprising)
    cyclops with earplugs (polite) (Great Monster Uprising)
    Walter M. Smith (c. 900-910 GUE)
    horned-cyclops skull, Flathead Beach (873 GUE)
    cyclops skull, Gray Mountain Asylum (948 GUE)

CYCLOPS (monoptic erectoclops)

A cyclops is a one-eyed giant, most easily twenty feet tall, with rows of long, sharp teeth. Although fairly rare in the Great Underground Empire, they present quite a problem when encountered. Though not very friendly, they like people. In fact, the average cyclops would quite willingly devour an average human, and love every bit of it if given the chance. So much of a nuisance were cyclops, that quite often one could find advertisements in Popular Enchanting posted by people looking for enchanters for cyclops eradication work.

Throughout the years only two methods of avoiding a cyclops have proven effective. One could either feed it something other than oneself (as they grow incredibly sleepy after any sizeable meal), or trick it into believing that you are Odysseus, its race's ancient nemesis, or that Odysseus is nearby. This name sends all cyclops fleeing in terror; even crashing through walls to escape the mere mention of this infamous menance. Aware of their vulnerability these certain words or phrases, by the eleventh century, cyclops have taken to using earplugs to prevent wily adventurers from avoiding combat.

While of the common tongue, the cyclops speech is usually a spitting out of a horrible assortment of syllables that are barely decipherable. Roaring, the cyclops pummels victims with both teeth and leaping strikes with whatever crude weapon it can manage (if none is present, fists are known to splat pests just as efficently). Cyclops also sleep like babies, albeit very ugly ones, and one should consider it a blessing to discover it in that condition, but woe to the one foolish enough to wake it!

Cyclops weapons are huge; much too heavy for even the strongest of men to lift. Without weapons, the cyclops is just as ferocious, crushing a human skull with one strike, ripping even the stockiest men to shreds, and breaking arms, legs, and necks with ease. Sometimes cyclops are so excited by their successful hits that they neglect to kill their victims, leaving them to wallow in pain. But after deciding whether to broil or stew its fresh dinner, it usually remembers to dispatch the catch instead of cooking it live (though the forgetful beasts have been known to do so).
Considering their rarity, the cyclops population experienced an unexpected boom during the Great Monster Uprising of the Second Age of Magic in which they massively spread into the mountainous regions all over Zork. Regions of cyclops sightings during that period include: Frigid River Valley (The White Cliffs and its beaches), Flathead Mountains, Flathead Fjord, The Gray Mountains (including the Gray Mountains Asylum and Mirror Lake), Grubbo Hills, Mithicus Mountains, The Lonely Mountain, Largoneth Castle, and the G.U.E. Tech Training Grounds in the Ethereal Plane of Atrii.

On a minor note, on a certain Frob Day and Star Day of the Great Monster Uprising, a certain gremlin inspired every cyclops in the world with a rare notion of politeness -- the signs they carried about read "Pardon?" instead of "I can't hear you!"

The period of history is vague between the end of the Great Monster Uprising and the First Great Diffusion (1247 GUE) until the Second Great Diffusion (1647 GUE). But it is known that by the time of the Second Great Diffusion that cyclops, as well as the entire Great Underground Empire, was considered mythology. Thus it may be concluded that the cyclops population either went extinct, was reduced so tremendously, or hid themselves in the deepest recesses of the underground, that there is no longer a trace of them in any known civilized portion of Zork (at least above ground).

SOURCE(S): Dungeon, Zork I, Zork II (The GUE on 9 Zorkmids a Day), Zork: Malifestro Quest, Enchanter (Popular Enchanting), Spellbreaker (sample transcript), Zork: Nemesis (game, design documents), Legends of Zork, Return to Zork