Anything heavy leaning up against something else, such as a framed picture
or mirror leaning against the wall.  A ferret could push the bottom out,
causing it to slide down flat and trap or crush him, or he might scale the
item and cause it to topple over, falling on him or another ferret playing
beneath.  The same goes for a heavy box or even a large bag of dog food
(believe it or not, the latter ALMOST happened to one of my guys!).  Lay
the item down flat, so there's no way it can fall over when ferrets are out
playing.
 
Nancy and critters
[Posted in FML issue 3405]