This morning, as a bit of a treat, my mom dropped a piece of scrambled egg into Gizmo's bowl. He struck his nose in like he was just sniffing, then whined and looked at her. He then looked under the bowl, around the bowl, up at her hand, etc.
The body language was perfectly readable. "Hey, wait! I thought you put something in here! I didn't get any! Mom, where is it?"
The egg somehow magically vanished while he was "just sniffing". I was pretty impressed at his sleight-of-muzzle, too. You would have never guessed that he'd chewed something and swallowed it--his jaw never moved.