noun- A person, usually a teenager or kid, who follows the mainstream just to fit in with others.
Most likely not know who they are, what they are doing, and not know what they are going to do later.
They tend to act differently in different occasions and/or groups.
See also Mainstream Whore.
This boy at my old Elementary was a regular boy. He has changed ever since he was introduced to Raves, Hardcore Music, Scene Hair, and lights. He has never been the same ever since. What a Mainstream Kid.