How could a cup of water that was left on a table end up on the floor, upside down, with the water still inside and not 1 drop on the floor?

So I come home from work one afternoon, and notice a cup I had placed on the dining room table was now on the floor – upside down and with the water still inside. I scan the floor for any trace of liquid, but there’s none – not 1 drop. Not believing my eyes, I pick up the cup, which immediately releases the h2o in all directions – just as one would expect. Now, I know for a fact I was the last to leave that morning and the first one home – no one had been there during the day with the exception of the kitty cat. So, what happened?