No Initial Appearance

Is it possible to have a portable thing which has no initial appearance? I want it to not be mentioned until handled, without leaving a big swath of white space in the room description.

Start it off as scenery, then, when taken, make it not scenery.

This works without having to set flags:

Rule for writing a paragraph about the not handled stone:
	now the stone is mentioned;

Aha, Zarf, that’s exactly what I was looking for. I tried using an empty rule, but of course it didn’t set the mentioned property.