How'd that get there?

I just found a blob of strawberry yogurt on the wall about 5 inches from the ceiling in the piano room!?!? I tried to take a picture of it, but the lighting just wasn't working. A little later I found Elmer's glue on the piano bench. No one would fess up to either of these delights. School just let out for the break, so I have a feeling my next two weeks will be filled with such findings. Oh the joys!!