Flapping Fish
Well, this didn't work out. The fish, once turned on (the switch is quite small), keeps flapping around until the battery runs out or I turn it off, even if the cat isn't playing with it. I used to have a fish that only started flapping when touched—if the cat ignored it, it wouldn't turn on. This one is also quite a bit noisier. What a pity. I won't buy it again, it actually scares the cat more than anything.