Don-Lu's Dog, an example of a brain in action.

Brains are used on creatures to give them basic AI. They come in two types, protected and unprotected.

Both types of brains can be destroyed by being activated by a sensor. However, unprotected brains can also be destroyed by being jumped on by a Sackperson or a Sackbot .

Brains are used to control creature legs and wheels, and are able to tell them to patrol (Changing directions when they reach a creature navigator), follow or flee from Sackboy, as well as jump during movement.