In a hotel the crew begin to clean all of the rooms. A man walks into a room and begins to clean. He sees a trunk and he removes it and places it on a table. As he puts the room back in order he reaches for the trunk but it refuses to move. He calls down the hall for others to come and help him put the trunk back. None can move the trunk. They try to open the trunk but it is locked and they cannot open it. They call to the office to find the key to the trunk. Meanwhile many enter the room to try and remove the trunk but it will not budge from the table.

Then in walks a woman and says, "I know why it wont move..."

What is in the trunk that allows you to lift onto the table but not off the table?