Okay, so, you enter a Devilite level, and there's a small chance that the first Devilite spawned will be a Kid Devilite, visiting his dad's workplace for Bring Your Child-Like Thing to Work day. The kid Devilite is invulnerable to all attacks and will follow you around spouting kid stuff ("When I grow up, I wanna be an astronaut, not an accountant!") He'll follow you throughout the entire level, and if you get to the end you can reunite him with his father, whow as looking for him the whole time.
And then you get some sort of crown reward or something and the family is reunited and everything's happy.
Actually this is just a vehicle for Kid Devilites.
I wanna see what one looks like.
/hug