In anatomy

Anatomy

Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

, an eyestalk (sometimes spelled as eye stalk or known as an ommatophore) is a protrusion that extends the eye away from the body, giving the eye a better field of view than if it were unextended. It is common in nature and in fiction.

In nature

In nature, eyestalks are sometimes called tentacle

Tentacle

A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...

s, and may have olfactory organs and/or eyes at the end. Examples include snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s, the trilobite superfamily Asaphoidea, and fly family Diopsidae. The crustacean family Polychelidae

Polychelidae

The family Polychelidae contains thirty-eight extant species of blind, benthic lobster-like crustaceans. They are found throughout the world's tropical, sub-tropical and temperate oceans, including the Mediterranean Sea and the Irish Sea.-Anatomy:...

 have eyestalks but no eye.

In fiction

A beholder

Beholder

The beholder is a fictional monster in the Dungeons & Dragons fantasy role-playing game. It resembles a floating orb of flesh with a large mouth, single central eye, and lots of smaller eyestalks on top with deadly magical powers....

 is a fictional character that sports numerous vertical eyestalks. Many Dalek variants

Dalek variants

Since their first appearance in 1963 there have been a number of variant models of the Daleks, a fictional alien race in the long-running BBC science fiction television programme Doctor Who.Daleks are not robots...

 have a horizontal eyestalk.

Tripods from Star Wars

Star Wars

Star Wars is an American epic space opera film series created by George Lucas. The first film in the series was originally released on May 25, 1977, under the title Star Wars, by 20th Century Fox, and became a worldwide pop culture phenomenon, followed by two sequels, released at three-year...

have eyestalks.