ChromaCakes are MACs version of standard theatrical pancake makeup. They are a hard heavily pigmented puck of makeup which is activated with water prior to use. ChromaCakes are used for large-area body painting and theatrical makeup effects.
ChromaCakes follow the same usage precautions as the PRO pigments of the same shade names, so while you may be able to use some of them in the eye or lip area, not all will work well in these areas.