Some really great creature designs involved in our newest project called Jump Jump Cookie. These fellows are the main antagonists of our app.
These were drawn in SAI Painter and cleaned up in Adobe Photoshop 5. I created the initial sketches for all of them in a plain old sketchbook with a ball pen. Always go back to the basics when you create the initial sketch. An ink pen prevents you from erasing your mistakes so that you can look at them and learn from them. Plus it keeps your art looking fresh.