Defender of Adam's bedroom against alien intruders.
He hears them from lightyears away.
He uses his hair to brush them nigh unto ticklishness, at which point they give up and fly away.
The sign also says, in big words that I didn't photograph: "BOO!!"
That should do it, if the tickling doesn't.
(As Adam's mom, I was just so proud of how he drew a person that actually LOOKED like a person that I just had to show it off. I think he's going to be the next great artiste of his generation, don't you think?)