They come under attack in the Play Set, first from the goo volcano, and then from Emperor Zurg, and it is the player's job to defend them from the threats that come their way, as well as helping them with various things around the planet. For example, the player can use the Medicine Ball to heal a sick or injured alien. The player also erects buildings to assist the aliens, including the Shield Tower (to protect the aliens from the hail of rocks spewing from the volcano), Decoration Center (to help spruce up their planet), Clothing Store (to clothe the aliens in order to help tell them apart), Hatchery (to hatch the eggs around the planet), and Hospital (to care for the sick and injured aliens). The aliens also give out many missions to the player. Such missions range from finding an injured alien to taking a tourist alien to a good picture taking spot. Occasionally, an alien will appear in the play set wearing a catcher's mitt and asking for the player to throw him a ball. If the player does so, the alien will give him sparks and crystals.
If the player collects the right capsules in the play set, the aliens will become available in toy box mode. There are many different variations on the alien that are unlockable toy box, all based on their various coatumes in toy box. They are as follows:
