Thanks for replying @blue_dolphin. Mystery is solved as I looked up from the well and found where the little thing fits. There are three holes on the side of the machine where there are screws and they are covered with these little 'plugs'....I notice now that it is not hollow. It must have fallen off the side of the machine into the well where the tank fits the last time I was filling the tank. It is back in it's place and no water was spilt! Sheesh.
Thanks.