I always think to get an idea of how these games look, go onto YouTube and search for it. It can be eye opening.
My eldest is 10 so I have no personal experience of it, but trolling sometimes occurs if they go online, ie an older boy/man will deliberately keep killing you to provoke a response.
You can tell that someone is young as they have a high pitched voice whilst telling the older person to go fuck themselves. I suppose that is amusing to some. Then the older person uploads it onto YouTube for their mates to laugh at.