Inside of Locker

I've not seen anything like this before so I'm having a hard time figuring out what this is in RL. I can see the coffin shape and get that you are repurposing it for minis but what does it do in RL? Is it what something was packaged in or is it a RL toy? Sorry to sound dumb.

Monster High is a range of 12 inch fashion dolls, all with monster names (like Draculaura and Frankie Stein). This is one of those side-line items marketed for teen girls to keep their bits & pieces in, a mini school locker to keep in their rooms. The music box plays the theme song from the DVD and makes screaming sounds as well.

Thanks for the explanation. My kiddos haven't been into this trend so I'm not up on it. Barbies and Legos are the main events around here.