In theory, this isn't really a gift but a part of another gift that needs these batteries to dance and shout obnoxious catch phrases, but I'm pretty sure that somewhere, someone bought a pack of 9V batteries for their kid's present and that's all the poor little bastard is getting because eToys recommends this "gift" for 8-year-olds. And that is sad. Here's a list of things to do with a battery when you don't have any stuff lying around that needs batteries:
Throwing at things
Peeing on it and then throwing it at things
Licking it and making your entire head vibrate like it just got struck by lightning
The third option is probably the best, since you can probably only throw the battery once or twice before you lose it and it will never explode, and peeing on it first is dirty. And licking a 9V battery is how 6-year-old kids brains get screwed up. They're too little to understand the whole concept of getting sloppy and TV teaches them that drugs have a lot to do with the eggs they ate earlier that morning. And there's nothing little kids like doing more than daring each other to hurt themselves. That's why I've only had one arm for the last 20 years and my face looks like it's made out of beehive. Live and learn.