Object permanence and humor

Tonight, Maddy was playing with some plastic lincoln connector things - one was a stick and one was a wheel. She loved to put the stick in her mouth, which was a problem for me. Every time I'd try to take it, she'd get so mad. So instead of trying to take it, I would just pull it out of her mouth. She had pulled up onto the couch and had the stick in her mouth and I decided to just take it and put it behind her on the coffee table. Whoa! It was like I had smacked her. She let out a yell that just shocked me. Boy did I make her mad. She got down, turned around and pulled up onto the coffee table and started looking. Her gaze went left and right. When she found it, she stopped crying, picked it up and smiled. Whoa!