Personally, I like the pigeon coop idea. But might I suggest that you ask your neighbor if he would move the light off the gutter and offer an attachment right to your fence, thus pointing the light the opposite direction rather than in your yard, but still allowing your neighbor to have the light where he wants it in his yard.
Then go out a couple of weeks later to paint your fence and “accidently” paint over the sensor. Use this opportunity to sneak into his bedroom for the next three nights and inject him with heroin. While he’s getting hooked, go through his bills and find his electric bill to get all the info you need to cancel his power. With his requirement of rehab, the cancellation of his power and the subsequent loss of his job, you stand a pretty good chance of destroying that flood light without anyone caring too much. Good luck.