The case of the missing "wa-wa"

For a period of ten or fifteen minutes yesterday I searched the kitchen, sunroom, living room for a purple Nalgene sippy cup full of milk.  I had just handed it to Lucia from the fridge and knew had taken some sips.  But where did she put the bottle down? I finally asked her, "where's your wa-wa?"  She looked puzzled, put her arms up with shrugged shoulders and started looking with me in all the rooms.  When my phone rang, I ran to pick it up.  She followed me back to the kitchen, said "Mommy," opened the cabinet door and found the missing bottle.