I once spawned a bandit_shopkeeper on the wrong spot, and they cannot be despawned either and by default have no owner. They are targeted by helis and NPCs like murderers, which can be problematic. There were various players online and I was trying to avoid restoring a backup (which I trigger every few hours).

I managed to remove it by first taking ownership of the entity with the Entity Owner plugin (be very careful with it, and don't forget to set the necessary permissions) and then using the entity.deletyby <steamid> command to delete all entities belonging to me. Only try this if you don't mind losing everything you've built or deployed.

Now I might be mistaken, but I think that stuff like that AK will disappear after a server restart.