As the Ghost Host talks, you start to notice the room is getting taller or as the name implies stretches right before your eyes. The portraits also stretch and show the whole story, so to speak.... Now this effect for a home haunt might be a little over the top. The mechanics alone to raise a roof is out of the reach of a lot of haunters. But the portrait idea could work. Think of a "drop panel" type set-up but without the fast loud drop. Build a drop panel with the panel lower so to cover half of a portrait. The portrait should have a normal looking feature on top and something weird, funny or scary on the bottom. Use a pneumatic piston to raise and lower the panel slowly to expose the lower half of the portrait. It's like one of those changing portrait ideas, but not. You could do this in a long hallway with a couple portraits or in a room with a single one. It's a good way to make people take a second look and wonder if the picture stretching or is it there imagination.