Check out this great writing tip in this post from Anna Dobritt’s blog on the topic of avoiding plot bunnies
A plot bunny is an idea that tends to multiply without warning, much like a pair of rabbits. The good point about plot bunnies, you will never run out of ideas for writing. The bad point, there’s not enough hours in the day or months in the year to write out every plot bunny that comes along. Much as you would like to write each one that appears, I fear your well-being will suffer. To help gain a semblance of control over plot bunnies, keep a notebook handy or create a word document and save it. Next time you are looking for something to write, go through the ideas you wrote down or typed up.