Concealing something in the inventory

Does anyone know if this is possible? I have a box that contains something that I don’t want the player to be able to see or interact with, but if the player picks up the box (which he needs to do) then the item will show up in the inventory as being in the box.

Is there any known way of stopping this from happening?

Thanks so much in advance

Only move the thing into the box when they pick it up for the first time.

If the player can’t see or interact with the thing, why does it have to be in the box?