"I haven't seen them freeze anything inorganic. Plants, other animals- anything living. If I can find a way to catch a few of them alive, I might be able to tell you more. But dissection should hopefully tell me something too.

He picks up his knife, with the mouse still skewered on it, careful not to touch the mouse itself, just in case. "We go outside, touch the mouse against the nearest tree and see what happens. Either we get some flash-frozen foliage, or nothing happens."

In terms of scientific methods, it's a little more advanced than "poke it with a stick and see what happens," but not by much. But an experiment is no less valuable for being simple.