You can bring one helper pet into any level. Before they can be used, helpers must be charged by either matching pets on the level or feeding them directly. Once full, you can use their special abilities. For example, Harold the Dog, the first helper, will match pets in a cross formation. Helpers can also be leveled up by collecting materials. The more stars you earn on a level, the more materials you will receive as a reward. This will also unlock additional helpers.