A demon possessed a mannequin, causing it to comes to life and transforms several people into mannequins.
The original manga where an anime episode is based of, there are many similarities in regards of the transformed people on the department store where the scene originally took place.
The manga features several people, in both genders that are fallen victims into the mannequin, which later afterwards were defeated by Mikami and her team. Upon its defeat, the victims are later reverted back.
The anime adaptation of the manga. Scenes in the episode followed the manga closely especially in the department store, apart for a few differences as there are two major characters being shown transformed in the anime - which isn't shown in the manga.
The same also observed on the plot, as the manga solely focused on the department store as the only place where the incident took place compared to the anime which consist of several other locations, in addition of extra victims as well.