Eyegore

Eyegores, also known as Rocklops and Eye Guards are large creatures with a single eye. Aside from the eye, they are invulnerable. They lay dormant and wait for Link to approach, waking and pursuing when he does so. The name is a pun on one of the pronunciations of the name "Igor."

The Legend of Zelda: A Link to the Past
Eyegores appear in many dungeons. They appear in green and red, and both wear orange cloths and capes. The green ones can be defeated with a thrown jar or arrow in the eye, while red ones require three arrows. They often appear in groups. Additionally, large Eyegore statues appear in the dungeons as well, often for decoration, and some holding Telepathy tiles. Most are gold, but one Eyegore statue, colored green, reveals a secret passage if shot in the eye. Similar Eyegore status are seen without Eyegores themselves in Link's Awakening and the Oracle games.

The Legend of Zelda: Majora's Mask
Two Eyegores appear in the Stone Tower Temple, both on the same bridge. They are depicted as large and slate-colored, having a thin torso with a large eye on top. The first one stomps slowly after Link, occasionally pounding the ground with its fists, which turns into blue eye yellow. From here, it can be damaged with the Hero's Bow or Hookshot, turning its eye red briefly. The second one is encountered when the temple is flipped. It attacks much the same, but it can fire lasers from its eye as well, also turning it yellow.

The Legend of Zelda: Four Swords Adventures
Eyegores are encountered en masse in one room of the Desert Temple. They act like their A Link to the Past appearance, but somewhat resemble the Eyegore Statues from Four Swords.

The Legend of Zelda: A Link Between Worlds
Eyegores appear mostly as they did in A Link to the Past. They are slightly taller, and additionally appear in blue, being medium-strength. Eyegores can now be attacked in the eye with the sword. Their eyes also function as headlamps in dark rooms. A quintet of red Eyegores appear as a mid-boss in the dark in Thieves' Hideout.

A Link to the Past comic
An Eyegore appears in the Palace of Darkness, where it catches a disguised Link trying to blow up the stockpile of Firecorn, and sends a group of "Gleeocks" after him.