Save a plastic bottle (8-12oz), wash it out, and remove the label.
Fill the bottle 3/4 of the way with water (leaving space to shake it up later).
I chose to use one bottle of silver glitter glue, but you could use regular glue instead if you prefer. You would probably need half of a bottle of regular glue.
Squeeze in all of the glue and shake the bottle to mix it together.
I used 6 drops of green food coloring.
Cap, and mix again.
I threw 12 round plastic gems in to add a nice rattle sound and to look a little bit like bubbles in a fish tank. I also dumped in a bunch if green glitter to add sparkle.
Super glue the cap to the bottle and wrap a few layers of electric or duct tape over it to strengthen the seal.
Add some stickers to the outside for a finished look. This bottle is small enough for my 2 year old to use on his own. It's a quiet and calming toy that you shake, then watch as everything settles.