While adventuring in the forest adventure with the treasure hunter, explore the line of three trees to the right. If your lucky, you'll find an item called "Strong Glue". The treasure hunter will tell you that it can be used on the item you receive by collecting 5 diomand marked cans of Cup Jelly. After finding the glue, feed your monster Cup Jelly (being carful not to let it get too skinny) until you collect five of the cups that have diomand marks on them (this happens randomly). Colt will automatically use the glue on the Quack Doll that comes in the mail a few weeks later. Use the glued Quack Doll as a secret seasoning in the lab when combining any two monsters and there's your Wooden Duck.