Freeze water balloons with food coloring in them. Seemed easy enough. I decided to try it.
First, I thought I could gently lay them in the grass to freeze. Nope, first one popped. Next I decided to put them on the porch where it is smooth and shady. Seemed fine but when I carried the second one out there Twist had popped the first one. Next step, lock kitten in cage. I also dropped one resulting in a complete clothing change and taking a squeegee to the porch.
I finally got them all done and left them to freeze. They didn't. I let it get colder. Finally after about two days I got this. Some of them broke and leaked all over the porch. Some sort of deflated and some were partly frozen.
In the end I got a few lightly tinted shells that look sort of like broken eggs.
I think I tried to make my balloons too big (bigger is better right?) and/or the weather was not cold enough. Maybe I'll get brave and try again.