How do you make a water grenade?

Fold a square sheet of paper diagonally,unfold, then repeat in the opposite direction. At this point, the shape of an "x" should be apparent from the folds. Turn the paper over, then fold in half from top to bottom. Turn it again, press in the middle, fold in the flaps on the side. The paper should be in the shape of a triangle. Fold the front-side flaps to the middle. The shape should now be square. Fold the side corners to the middle. Pockets should form, tuck the flaps into the pockets. Repeat the steps on the opposite side. Blow in a little hole to inflate it. Fill with water.