How about Laser FPV robot in your home?
As you see the sky is the limit.
All you need to do is connect properly powerful 2W death ray laser with digital camera and radio transmitter. After that you just put all this stuff in drone bot and you are ready to shot your nosy neighbor , sitting in a front of your tv 😉 Just kidding ];->
Ok but now seriously. You can buy some baloons and shoot to them in your apartment. It’s great fun and you won’t have problems with the law 🙂