Caterpillar Birthday Cake

I made this for my nephew's first birthday. I purchased a round ball pan from a craft store (Wilton Brand, Sports Ball Pan). All of the balls are cake except for the smallest - for that one I frosted a mini doughnut hole and used a toothpick to hold it in place. The wheels are frosted and layered cookies, and the grass is coconut that I colored with green gel food coloring. I also used fruit roll-ups for the antenna.