I still have about 2/3rds of a box of the exact ones you speak of. They're pretty useless. I suppose the snake/mouse thing has validity to it, If you put the iron to it's head and squeeze the trigger. As for pigeons and swallows, it's been said before. Useless.
Keep in mind that they might not cycle semi-automatics, my Savage 64 didn't like them. I also had problems with some of them extracting from the chamber. It almost looks as though the brass bit into the rifling.
I don't consider the 11 bucks I paid for the box a waste, as they were fun to try out and now I know what they do. That being said, my $40 Savage pump shotgun is far more effective.