Water bombs?

It's a pity I have no pictures to show.

While walking ST home, I saw on the floor about 2 dozen plastic drinks holders, shaped in the form of hand grenades. The floor was marked with splatter patterns.

My first thought, "Are kids throwing syrup drinking "cups" as water bombs these days? What the?!!"

Later I reasoned that they probably filled them up with water for play but left them for the cleaners..

-.-"