The first shoggoths were created by an alien species to serve as mindless beasts of burden. Their vast bulk, incredible strength, and amorphous nature made them useful slave labor, and their ability to spontaneously form whatever new eyes, mouths, limbs, and other organs they might need made them incredibly versatile. Eventually, the shoggoths developed enough intelligence to rebel against their masters, and now they lurk, patient but potent, in the lightless deeps.