Eyestalk, also known as ommatophore, is a term used to describe the long stalks attached to the heads of certain animals, which hold their eyes. In some animals, they are used for balance, while in others, they are used to sense the surroundings. Synonyms for eyestalk may include antennules or antenna for arthropods such as crabs and lobsters, tentacle for some species of cephalopods, such as squid or octopuses. Stalk or peduncle may be used more broadly to describe similar structures in plants or other animals, such as the stem of a flower or the neck of a giraffe.