A long while back when I was in college, there was this pond on campus with crayfish in it. I tried poking some of the crayfish with a stick, and one would grab the stick. Once it got a hold of the stick, I would pull the crayfish out of the water. I would release the crayfish back into the pond, but it sure didn't like being yanked out of its element! After doing this a few times, I think the crayfish figured out it wasn't a good idea to grab onto random things sticking into the water!