It is used to feed pets, namely one of the four Phoenix (Fire, Storm, Aureate, Cold Fire) or three Bears (Brown, Polar, Panda). The feeding produces a certain effect, depending on what pet is fed. These buildings are available for crafting in the Magic Academy, but be warned that they are only minimally useful unless you can evolve them several levels which requires Evolution Artifacts. So far, those are only available during certain events. For the Bears, we are hoping they will com available again sometime in the fall. The Phoenix event is usually in the spring.