If he decides he wants to continue being a jerk....well, I'm in a fun mood. This was suggested on another site:
1) Buy a disposable cell phone, pay as you go. Buy firecrackers too.
2) Call cops and report someone of his description entering the house with what appeared to be a handgun.
3) Wait for cops to show up.
4) As they open their car door and start walking up walkway to his house, toss lit firecracker over fence into his back yard.
5)Mention nothing to the neighbor, but crack a wide smile each time you see him.
6) Repeat steps 1 to 5 as needed.