Whenever I have lived in Southeast Asia, I have seen people setting off fireworks to scare away evil spirits. Conch shells and sometimes other loud musical instruments are supposed to have the same effect. Likewise sambrani and camphor.
I always wondered where the evil spirits were going off to having been thus terrified. Did they ever realize that they had been duped? After all, as immaterial beings, fireworks, conch shells, and incense are no real threat to them. Why were they even scared away by these things in the first place? Were they only startled by them?
Then I started to wonder if maybe they were all going to come back at once at some point and wreck havoc, having understood the futility of human preventative measures against their influences.
Could be.
Sorry for bothering you before, evil spirits.