No no...it's not what you think! A mattress IS involved but not how you think. I bought a new set of bunkbeds for my son. It's a twin over a full. I had to order a new mattress for the full portion since his last bunkbed was a twin over a twin.
The mattress came and it was in this SMALL box. I looked at it and thought "What the heck did I order?!!!" I thought for SURE I ordered a full 8 inch deep inner spring mattress but this box looked to be one that held just a memory foam topper or something. My DH opened the box and pull it out...slowly it started to unfold....after a minute or two...I yelled for him to quickly help me get it upstairs because if it completely opened we would struggle with it. We grabbed it and as quickly as we could got it up the stairs and just as we hit the top...it popped open.
It is indeed a full size inner spring mattress!!! I'm still amazed!!!! How did they get this thing in a small box? The box was only about 3' high...a foot and a half feet wide and a foot and a half feet deep.