What would happen if you dropped rubidium metal into a beaker of water?

As you may know, as you go down the Periodic Table in any one column of metals, each one is more reactive than the previous. So I would expect the experiment to be very violent! Sodium dropped into water, begins to bubble and moves around the water rapidly. Rubidium would do so also, but much more violently and more quickly. Please don't try this at home!