Fit the decorating bag with tip 12 and fill 1/2 full with medium constistency icing. Hold the bag and tip at slightly less than 90° angle slightly above surface of your cake. Pipe tip 12 large ball head using the build-up technique. To complete your shape, stop squeezing as you bring the end of the tip to the surface. Use the edge of the tip to shave off any point so that your mound is nicely rounded.
With tip 1, add dot eyes and nose and a string mouth.
Add tip 3 lines, close together for hair.