A young over-enthusiastic admirer. May refer to you on a first name basis or even speak to you as if you've been friends for years. You only know them on an impersonal level but they see it as something closer. Usually means well but comes off as creepy or obsessed.
Little Buddy: Hey how's it going! How's your wife and corgi? Do you need any help with that big project I heard you're working on? I started working on it last night just in case you did.
You: Uh hi, maybe. Lets wait and see...
Little Buddy: Ok cool, thanks! I'll get right on that! Tell your brother I say hello!