Sugar Skull Brush Tool-
Please follow this link- http://gomedia.com/zine/tutorials/a-pseudo-sugar-skull-from-start-to-finish/ for more detail instructions and step by step. The video below will help you achieve the brush tool aspect of this.
Direction on how to draw a skull can be found here:
https://design.tutsplus.com/tutorials/how-to-draw-a-skull--cms-29172
