can anyone explain how to stop certain bat night events

I'm having this exact same issue. I'm about to hop onto Manage Households and delete all of those damn aliens.

I like having aliens in the game but not like this. If they at least used their disguises but they never do it's really annoying. I hate the fact that bars have the ghosts and alien nights, because you just know they will plague your game to no end when you go to one. I avoid going to this venue because of it and it's one of my favourite venues to take my sims to.