Stacey (STACEY) is a witch that appears as a boss in Puella Magi Madoka Magica Side Story: Magia Record.
In the rooftop graced by fine weather, the witch is lost in dreams of “what if”s. She indulges in dozing and lazing, thinking only of things that will not become true, in absolute bliss. So that the witch does not fly off the roof in her unsteady balance and become a missing person, the witch is confined to the roof - her base is strapped down and the door is locked. However, since the witch is always on the roof, this state of affairs does not seem to bother her - instead, she picks a fight only with those that disturb her dreams. By the way, it seems the giant profile cameo drawn on the brooch is completely irrelevant to her.
It frets and worries about whether the daydreaming witch is going to jump off the rooftop. Whether it is locking the school doors, moving about sweeping the floors or pointing and calling, it's completely devoted to the task. It is in charge of the keys to the rooftop where the witch is but it frequently looses them due to its own carelessness. Therefore its fellow minions hold duplicate keys but, if any one of them falls over the state of security on the way to the rooftop would.. how careless. It finds any intruders to this completely closed-off barrier detestable. If any are found, all surrounding minions would quickly gather and attack while dynamically waving around their very important key.