A cyst

A cyst is a structure that is formed from outer and inner layers surrounded by a transparent membrane. It is found in the body of many animals and plants, as well as in some protozoa and fungi. Cysts can be hard or soft, able to move or remain stationary.

Cysts can have different sizes and shapes, but most often they resemble a circle or oval. The outer layer consists of dense cells that protect the inner layer from damage and penetration of microbes. The inner layer contains various organelles and cells that are necessary to maintain the vital functions of the body.