He is first located in the Spooky Forest near some bats and a bridge. He is standing on a stump on a tree.
The second time, he is located in the Walking The Path level. He is around the bridge where you meet the troll and save the goat. He is on the little piece of land when you jump off the bridge. You may need to use a high jumper to get to the other side.
The last time you will see him is in the Prison Break level, where there is a troll and one of the Pork Chop Brothers is trapped in the cage. Take the ball, roll it up the hill, put it on the weigher, then roll the ball back down hill. It will bust open the gate. Then, go up the stairs to find him.