Magnified Movements Activity

Each scout silently chooses one other scout to mimic.
Whenever that other scout moves, the scout should copy the movement, making it a tiny bit bigger.

If everyone remains frozen and not moving, ask all scouts with a [pet dog, older brother, birthday this month, ...] to slightly move any body part once.
That should prime the pump and get things going.

There is no 'winning', but the activity should build as the slight movements become magnified. Have an obvious signal, such as a whistle, to stop the commotion.