A nozzle that sprayed gasoline across the front porch when the front door frame is damaged would be interesting. Fire a round, officer, and poof you’d go up in flames. Nothing the homeowner can do if you want to commit suicide.
A decade or more ago, we actually had a legislator propose a law in Arizona making it illegal to fortify homes... because if made it difficult for police raids.
Fortunately, it did not go anywhere.