This is so funny, but first a little information leading to the humor.
Zack is wearing a Hollywood Undead shirt that he got from a concert is father took him to. On the front is these crazy looking guys in masks. On the back is a bird flying and carrying a grenade, in its claws. So as he is doing his chores he comes running into the living room, and says
"MOM IS THERE A BUG ON MY BACK" (yes he is yelling)
"Turn around." I say
"Look, mom, LOOK" he again yells
"No Zack just a bird with a grenade" I tell him
He starts crying and whining, "Get it off, Get it off, hurry up and get it off."
I am laughing because it is the picture on the back of his shirt.
"Its not funny, get it off"he says
Now he mad because I am laughing.
"Oh wait" he says, "Mom that is not a bug that is my shirt, this is not funny."
He then went back to doing his chores and telling me how mean I am.