What is an intrusive thought?
They are unwelcome involuntary thoughts, images, or unpleasant ideas that may become obsessions, are upsetting or distressing, and can be difficult to manage or eliminate.
Things that one may never forget, sometimes they are gruesome, sometimes mild, sometimes harmless.
It all depends.
You could envision yourself, murdering children, and women, and men, slaughtering their families, killing their pets, their cousins and their pets, their neighbors, everyone. One big bloody mess. More than once could you envision yourself going on murdering sprees, sometimes they are even worse.
You could envision yourself petting a puppy, and then ripping its head off just because you can. It can destroy your sanity.
Sometimes you envision plane flights, enjoyable at first... Until an engine explodes.
The side of the plane is ripped open, people are flung out of the opening, and people all around you are screaming. The explosion from the engine splattered somebody all over the wall and blood is covering you. The plane crashes into the ocean and you slowly drown, locked into your seat because the stress clouded your mind. Your life ended in that vision, and then you come back to reality sweating and crying your eyes out from how terrifying it was.
You could envision being kidnapped and sold into slavery, raped multiple times, abused and forced to work without pay, and without sleep or food, or drink. You are stuck in some place you didn't ask to be in without any rights. Nightmares plague you at night when you are allowed to sleep. The food you are occasionally allowed to eat is moldy or stale, the drinks are old and sometimes stagnant.
You could envision watching your family murdered in front of your eyes, and being left alone in the house with your family that is now dead. You sit and you cry and you cry, and you beg them to wake up, even though you know they won't. The police arrive and you can't even answer their questions. Then you are put up for adoption and then you are adopted by an incredibly abusive family, who beat you up and make fun of you daily, refuse to feed you, don't get you new clothing. Eventually you kill yourself from the stress because you can take no more of it.
You could envision yourself falling, doesn't matter where from. You just fall, and you fall and you fall. You don't know when it will end but it just ever does. And then right as you are going to hit the ground you stop and you come back to reality and realize
It was all just an Intrusive Thought.
Perhaps all the murderers we hear about are just stuck in a real intrusive thought, and they went insane, and started really doing what they see.
Maybe there is one that is about to go around, achieving the reality of his intrusive thoughts near your house right now.
Or, how do we know that they're even intrusive thoughts?
Maybe they're memories from previous lives, coming back to you, proving that people who have them may have been murdered, or were the murderers. Or the victims of one of these things. What do we know about reality, and illusions?