Amoebas are able to protect themselves from unfavorable conditions by forming a capsid cyst pseudopodium cell wall

Cyst

Amoeba is a unicellular organism, which exhibits an ability to alter it's shape. It is a common freshwater organism. It exhibit numerous psuedopodia that facilitates it's movement and grabbing the food particles.  

During adverse environmental conditions the ameoba survive by secreting a cyst. The amoeba becomes spherical in shape, loses the moist from it's cells and secretes a cyst membrane that serves as a protective covering around the cell. The covering rupture under favorable conditions and amoeba emerges out.