Squid usually have two tentacles and eight arms that are also called legs. A giant squid's tentacles can be up to 10 meters long, and the arms up to 3 meters long. The smallest squid is only 2.5 centimeters in length.

Squid have hooks that lie on the suckers of the tentacles. These are used to grab prey. Squid have the largest nervous system in the animal kingdom. They have the ability to change colors because they have translucent skin. The colors come from chromatophores, which are pigment cells that are on the outside of the skin that expand or contract to show colors.